Detailed Instructions: In this task, you're given a question, along with a context passage which has extra information available on certain terms mentioned in it. Your job is to determine which sentence(s) from the passage can be used to search for further information needed to answer the question.
Q: Question: How many years had Carlisle United been playing football for by the year Boulding went professional? Passage:Boulding maintained his links with football and trained with Doncaster Rovers, and in 1998 he joined non-league Hallam near his home in Sheffield. His form at Hallam attracted the interest of a number of league clubs, and Boulding was offered a trial by Mansfield Town. He was given a contract by the Division Three side and turned professional in 1999, which brought an end to his tennis career. He made his debut with Mansfield in a League Cup game against Nottingham Forest on 11 August 1999 as a late substitute for Gary Tallon, before his first league game came three days later against Cheltenham Town. He had to wait until his 12th game as a professional to register his first goal when he scored in a 2–1 victory over Shrewsbury Town on 23 October. He eventually finished his first season with six goals with Mansfield coming 17th but 17 points above Carlisle United, the only side to be relegated out of The Football League.

A:
He was given a contract by the Division Three side and turned professional in 1999, which brought an end to his tennis career