Given the question: Information:  - England is a country that is part of the United Kingdom. It shares land borders with Scotland to the north and Wales to the west. The Irish Sea lies northwest of England and the Celtic Sea lies to the southwest. England is separated from continental Europe by the North Sea to the east and the English Channel to the south. The country covers five-eighths of the island of Great Britain (which lies in the North Atlantic) in its centre and south; and includes over 100 smaller islands such as the Isles of Scilly, and the Isle of Wight.  - Rugby union, or simply rugby, is a contact team sport which originated in England in the first half of the 19th century. One of the two codes of rugby football, it is based on running with the ball in hand. In its most common form, a game is between two teams of 15 players using an oval-shaped ball on a rectangular field with H-shaped goalposts on each try line.  - Carmarthenshire (or informally "Sir Gâr") is a unitary authority in the south-west of Wales and is the largest of the thirteen historic counties of Wales. The three largest towns are Llanelli, Carmarthen and Ammanford. Carmarthen is the county town and administrative centre of Carmarthenshire, but the most populous settlement is Llanelli.  - Carmarthen ( "Merlin's fort") is a community in, and the county town of, Carmarthenshire, Wales. It is on the River Towy north of its mouth at Carmarthen Bay. In 2001, the population was 15,854.  - Luke Charteris (born 9 March 1983) is a Wales international rugby union player. His position is lock.  - Derwyn Jones ( born 14 November 1970 Carmarthen , Wales ) is a former professional Welsh rugby union player and Welsh international . A mountain of a player , he is 6 ft 10 inches tall ( the tallest Welsh rugby player until Luke Charteris was capped ) and weighed over 20 stone at his peak .    After reading the paragraphs above, we are interested in knowing the entity with which 'derwyn jones' exhibits the relationship of 'position played on team / speciality'. Find the answer from the choices below.  Choices: - centre  - lock
The answer is:
lock