The correct option is E All I, II and III
From II, we know that Copal's brother was born in 1982.
From III, we find that Gopal's brother was 8 years younger to him i.e. Gopal was born in 1974.
From I, we find that Sanjay is 6 years older than Gopal. Thus, Sanjay was born in 1968.