Mercury spins on its axis?

A)in about 3 Earth months B)in about 1 Earth week C)in about 2 Earth days D)in about 1 Earth month E)in about 2 Earth months F)in the same time as Mercury takes to go around the Sun, so it always keeps the same face toward the Sun I am not sure which one it is I think its either F or A . The rotation for Mercury and its orbit gives and nights about three months so I picked A and it was wrong. I am not sure if it is F can someone explain why A was not the answer and if F is also wrong.