They are all good. I use the
first one because it is more popular where I live, but I think the second version seems a bit more
clear.
The third version is used to indicate that someone
is no longer a child but is a man (male + adult).
MAN: (Version A)
The first part of this sign is similar to the sign "father" and then moves
down to touch the chest.



MAN: (Version B)



MAN: (Version C)



See: boy
See: girl
See:
Boy & Girl