Given the question: Information:  - A lighthouse is a tower, building, or other type of structure designed to emit light from a system of lamps and lenses, and to serve as a navigational aid for maritime pilots at sea or on inland waterways.  - The United States Lighthouse Board was the second agency of the US Federal Government, under the Department of Treasury, responsible for the construction and maintenance of all lighthouses and navigation aids in the United States, between 1852 and 1910. The new agency was created following complaints of the shipping industry of the previous administration of lighthouses under the Treasury's Lighthouse Establishment, which had had jurisdiction since 1791, and since 1820, been under the control of Stephen Pleasonton. The quasi-military board first met on April 28, 1851 and with its establishment, the administration of lighthouses and other aids to navigation would take their largest leap toward modernization since the inception of federal government control. In 1910, the Lighthouse Board was disestablished in favor of a more civilian Lighthouse Service, under the Department of Commerce; later the Lighthouse Service was merged into the United States Coast Guard in 1939.  - The United States Lighthouse Service, also known as the Bureau of Lighthouses, was the agency of the United States Government and the General Lighthouse Authority for the United States from the time of its creation in 1910 as the successor of the United States Lighthouse Board until 1939 when it was merged into the United States Coast Guard. It was responsible for the upkeep and maintenance of all lighthouses and lightvessels in the United States.  - A lighthouse tender is a ship specifically designed to maintain, support, or tend to lighthouses or lightvessels, providing supplies, fuel, mail, and transportation.  - A lightvessel, or lightship, is a ship which acts as a lighthouse. They are used in waters that are too deep or otherwise unsuitable for lighthouse construction. Although there is some record of fire beacons placed on ships in Roman times, the first modern lightvessel was off the Nore sandbank at the mouth of the River Thames in England, placed there by its inventor Robert Hamblin in 1734. The type has become largely obsolete; some stations were replaced by lighthouses as the construction techniques for the latter advanced, while others were replaced by large automated buoys.  - The three general lighthouse authorities are the agencies primarily responsible for aids to navigation in the United Kingdom and Ireland. They are divided into regions as follows:  - The USLHT Azalea , briefly the USS Azalea was a lighthouse tender built in 1891 for the United States Lighthouse Service . She was transferred to the United States Navy on 16 April 1917 and commissioned 9 May 1917 . Her role in the Navy was to salvage navigational aids , adjust buoys , and tended nets during World War I. She was returned to the Lighthouse service 1 July 1919 . She returned to duty in the Second Light House District . Azalea collided with the schooner Lavinia M. Snow off Pollock Rip in 1921 but was repaired and returned to service . She was decommissioned and sold in 1933 .  - The United States Coast Guard (USCG) is a branch of the United States Armed Forces and one of the country's seven uniformed services. The Coast Guard is a maritime, military, multi-mission service unique among the U.S. military branches for having a maritime law enforcement mission (with jurisdiction in both domestic and international waters) and a federal regulatory agency mission as part of its mission set. It operates under the U.S. Department of Homeland Security during peacetime, and can be transferred to the U.S. Department of the Navy by the U.S. President at any time, or by the U.S. Congress during times of war. This has happened twice, in 1917, during World War I, and in 1941, during World War II.    After reading the paragraphs above, we are interested in knowing the entity with which 'uslht azalea' exhibits the relationship of 'instance of'. Find the answer from the choices below.  Choices: - administration  - agency  - armed forces  - branch  - building  - coast  - coast guard  - country  - government  - industry  - jurisdiction  - lighthouse  - military  - mission  - navigational aid  - navy  - part  - river  - security  - service  - set  - seven  - ship  - system  - three  - tower  - war
The answer is:
ship