Which of the following letter-number clusters will replace the question mark (?) in the given series to make it logically complete?
SM13, QK25, OI37, MG49, ?​​

Given: SM13, QK25, OI37, MG49, ?

Logic: Letters are decreasing - 2 and number increasing + 12 place.

For, letter

S - 2 = Q, Q - 2 = O, O - 2 = M, M - 2 = K

M - 2 = K, K - 2 = I, I - 2 = G, G - 2 = E

For, number 

13 + 12 = 25, 25 + 12 = 37, 37 + 12 = 49, 49 + 12 = 61

So, the missing term is KE61.

Thus, correct option is (c).