Information:  - Dublin is the capital and largest city of Ireland. Dublin is in the province of Leinster on Ireland's east coast, at the mouth of the River Liffey. The city has an urban area population of 1,345,402. The population of the Greater Dublin Area, , was 1,904,806 people.  - A river is a natural flowing watercourse, usually freshwater, flowing towards an ocean, sea, lake or another river. In some cases a river flows into the ground and becomes dry at the end of its course without reaching another body of water. Small rivers can be referred to using names such as stream, creek, brook, rivulet, and rill. There are no official definitions for the generic term river as applied to geographic features, although in some countries or communities a stream is defined by its size. Many names for small rivers are specific to geographic location; examples are "run" in some parts of the United States, "burn" in Scotland and northeast England, and "beck" in northern England. Sometimes a river is defined as being larger than a creek, but not always: the language is vague.  - Dundalk is the county town of County Louth, Ireland. It is on the Castletown River, which flows into Dundalk Bay, and is near the border with Northern Ireland, halfway between Dublin and Belfast. Its has associations with the mythical warrior hero Cú Chulainn.  - Lough Neagh (pronounced ) is a large freshwater lake in Northern Ireland. It is the largest lake by area in the British Isles, with a surface area of . It supplies 40% of Northern Ireland's water. Its main inflows are the Upper River Bann and River Blackwater, and its main outflow is the Lower River Bann. Its name comes. The lough is owned by the Earl of Shaftesbury.  - An estuary is a partially enclosed coastal body of brackish water with one or more rivers or streams flowing into it, and with a free connection to the open sea.  - The River Fane ( Irish : Abhainn Átha Féan ) is a river originating in Lough Ross on the border of County Monaghan and County Armagh . It then flows east towards Dundalk Bay , straddling the border between Counties Monaghan , Louth and Armagh flowing through Inniskeen , Knockbridge , before meeting Dundalk Bay near Blackrock , County Louth . The Fane River is 38.25 miles long and drains an area of 350km2 It is , through the Cavan Hill pumping station , a major source of fresh water for Dundalk and the surrounding area in North Louth .  - County Monaghan is a county in Ireland. It is part of the Border Region and is in the province of Ulster. It is named after the town of Monaghan. Monaghan County Council is the local authority for the county. The population of the county is 60,483 according to the 2011 census. The county has existed since 1585, when the Mac Mathghamhna rulers of Airgíalla agreed to join the Kingdom of Ireland. Following the Irish War of Independence and the signing of the Anglo-Irish Treaty, Monaghan was one of three Ulster counties to join the Irish Free State rather than Northern Ireland.  - A County town is usually the location of administrative or judicial functions within the county, or it has been established over time as the "de facto" main town of a county. The concept of a county town eventually became detached from its original meaning of where the county administration or county hall is based. In fact, many county towns are no longer part of the administrative county. For example, Nottingham is administered by a unitary authority entirely separate from the rest of Nottinghamshire. Many county towns are classified as cities, but all are referred to as county towns regardless of whether city status is held or not.  - Dundalk Bay is a large (33 km), exposed estuary on the east coast of Ireland.  The inner bay is shallow, sandy and intertidal, though it slopes into a deeper area 2 km from the transitional water boundary. It is predominantly influenced by the sea, though several rivers drain into the bay from the west. In the northwest corner of the bay, the Castletown River cuts through the intertidal zone and the smaller River Fane flows into the southeast corner. While the bay is largely made up of intertidal flats, there is a significant area of salt marsh on the western shore. The catchment around the bay is of mixed agriculture and urban land use. The Castletown River is routinely dredged for navigation purposes for the deep water port of Dundalk. Rivers. Rivers which flow into Dundalk Bay:  - Northern Ireland (; Ulster Scots: "") is a top-level constituent unit of the United Kingdom in the northeast of Ireland. It is variously described as a country, province, region, or "part" of the United Kingdom, amongst other terms. Northern Ireland shares a border to the south and west with the Republic of Ireland. In 2011, its population was 1,810,863, constituting about 30% of the island's total population and about 3% of the UK's population. Established by the Northern Ireland Act 1998 as part of the Good Friday Agreement, the Northern Ireland Assembly holds responsibility for a range of devolved policy matters, while other areas are reserved for the British government. Northern Ireland co-operates with the Republic of Ireland in some areas, and the Agreement granted the Republic the ability to "put forward views and proposals" with "determined efforts to resolve disagreements between the two governments".  - Ireland (Ulster-Scots: ) is an island in the North Atlantic. It is separated from Great Britain to its east by the North Channel, the Irish Sea, and St George's Channel. Ireland is the second-largest island of the British Isles, the third-largest in Europe, and the twentieth-largest on Earth.  - The Castletown River is a river which flows through the town of Dundalk, County Louth, Ireland. It rises near Newtownhamilton, County Armagh, Northern Ireland, and is known as the Creggan River in its upper reaches. Its two main tributaries are the Kilcurry and Falmore rivers and it enters the Irish Sea at Dundalk Bay on the east coast of Ireland. The Castletown River flows in at the northwest corner of Dundalk Bay creating a deep channel through the intertidal zone. It is routinely dredged for navigation purposes for the deep water port of Dundalk.  - County Armagh (named after its county town, Armagh) is one of six counties that form Northern Ireland and one of the 32 traditional counties of Ireland, situated in the northeast of the island. Adjoined to the southern shore of Lough Neagh, the county covers an area of 1,326 km² and has a population of about 174,792. It is within the historic province of Ulster. County Armagh is known as the "Orchard County" because of its many apple orchards.  - Ulster (or "Cúige Uladh" , Ulster Scots: "Ulstèr" or "Ulster") is a province in the north of the island of Ireland. In ancient Ireland, it was one of the fifths ruled by a "rí ruirech", or "king of over-kings".  - Cú Chulainn, also spelt Cú Chulaind or Cúchulainn (Irish for "Culann's Hound") and sometimes known in English as Cuhullin , is an Irish mythological hero who appears in the stories of the Ulster Cycle, as well as in Scottish and Manx folklore. He is believed to be an incarnation of the god Lugh, who is also his father. His mother is the mortal Deichtine, sister of Conchobar mac Nessa.    After reading the paragraphs above, we are interested in knowing the entity with which 'river fane' exhibits the relationship of 'mouth of the watercourse'. Find the answer from the choices below.  Choices: - irish sea  - liffey  - main  - sea  - ulster
A:
irish sea