Correct option is C
Given:
GNK, IPM, KRO, MTQ, ?

Logic:
First Letter +2, Second Letter +2, Third Letter+2.
Solution:
First Letter: G+2 = I, I+2 = K, K+2 = M, M+2 = O
Second Letter: N+O = P, P+2 = R, R+2 = T, T+2 = V
Third Letter: K+2 = M, M+2 = O, O+2 = Q, Q+2 = S
The next series is OVS.
Thus, the correct option is (c).