1.  CMM, EOO, GQQ, _____, KUU

A. GRR
B. GSS
C. ISS
D. ITT

Answer: Option C

Explanation:

The first letters are in alphabetical order with a letter skipped in between each segment: C, E, G, I, K. The second and third letters are repeated; they are also in order with a skipped letter: M, O, Q, S, U.