What should come in place of the question mark (?) in the given series based on the English alphabetical order?
BCG, EFJ, HIM, KLP, ? 

Given: BCG, EFJ, HIM, KLP, ? 

​Logic: Each letter in the group increases by +3 alphabetically.

B + 3 = E
E + 3 = H
H + 3 = K
K + 3 = N

C + 3 = F
F + 3 = I
I + 3 = L
L + 3 = O

G + 3 = J
J + 3 = M
M + 3 = P
P + 3 = S

So, the next group = NOS

Thus, the correct option is (a) NOS