Correct option is A
Given: CLPM, FNQN, ?, LRSP, OTTQ
Logic: - first , second, third and fourth letter of each term increased by 3, 2, 1, 1 respectively.

C → F → I → L → O (+3 each step)
L → N → P → R → T (+2 each step)
P → Q → R → S → T (+1 each step)
M → N → O → P → Q (+1 each step)
So the missing cluster: I P R O
Final Answer:
The missing letter cluster is IPRO.
Final Correct Option:
(A) ️