For a given principal level n = 4, the energy of its subshells is in the order

Q. For a given principal level n = 4, the energy of its subshells is in the order

A.            s < p < d < f

B.            s > p > d > f

C.            s < p < f < d

D.            f < p < d < s

Answer: s < p < d < f