Who is the heaviest man?A is heavier than CC is heavier than DC is heavier than BD is heavier than BC is not heavier than A

A is heavier than C ⇒ A > C
C is heavier than D ⇒ C > D
C is heavier than B ⇒ C > B
D is heavier than B ⇒ D > B
C is not heavier than A ⇒ A > C
D > B 
C > B
C > D
A > C
Therefore A is the heaviest man.