Why does Si have a larger atomic radius than C?

A) The valence electrons in C feel a stronger effective nuclear charge than those in Si.

B) Si is lower down the group than C.

C) The valence electrons in Si feel a stronger effective nuclear charge than those in C.

D) The valence electrons in Si and C feel a similar Z _eff . Those in C are in a higher energy level.

E) The valence electrons in Si and C feel a similar Z _eff . Those in Si are in a higher energy level.