Question: John Alexander is the uncle of an English professional footballer who made his senior debut in what year?
Related documents: [0]  [DOC] John Alexander (born 5 October 1955) is an English former footballer who holds the post of club secretary at Manchester United. Born in Liverpool, Alexander began his football career with a club called Ulysses, before being picked up by Millwall, for whom he made his league debut in 1976. After scoring twice in 15 appearances over the course of two years with Millwall, he moved to Reading; he enjoyed greater success with Reading, scoring nine goals in 25 games. In 1981, he joined Northampton Town, but spent just one season with them before retiring from football at the age of 26 in 1982. Upon retiring from football, Alexander got a job with the BBC, but he later returned to football as club secretary at Watford. In 2000, he took up the same post at Tottenham Hotspur, spending 10 years there before applying for the same job at Manchester United, where he would replace the retiring Ken Ramsden. He took over at Manchester United on 1 July 2010. He is the uncle of Liverpool player Trent Alexander-Arnold. [END] 
[1]  [DOC] Trent John Alexander-Arnold (born 7 October 1998) is an English professional footballer who plays as a right-back for Premier League club Liverpool. He is an academy graduate of Liverpool and made his senior debut for the club in 2016, aged 18. The following year, he won the club's Young Player of the Season award. He has also represented England at all youth levels from under-16 through to under-19. Due to the length of his name, his surname is shortened to Alexander for Premier League fixtures. [END] 
Answer: 
2016
2016