1.  Z, X, S, I, R, R, ?, ?
A. G,I
B. J, I
C. J,K
D. K,M

Answer: Option A

Explanation:


Note that the numbers representing the difference between the consecutive terms of the series again from a series - 2, 5, 10, 17, 26, 37, 50 - in which the pattern is +3, +5, +7, +9, +11, +13.