Correct option is C
Given:
Series: MR25, NS33, OT41, PU49, ?

Logic: Letters are increasing by 1 and number is increasing by 8.
Find separate patterns for letters and numbers.
First Letters:
M → N → O → P → Q (+1 each)
Second Letters:
R → S → T → U → V (+1 each)
Numbers:
25 → 33 → 41 → 49
Differences:
33 - 25 = 8
41 - 33 = 8
49 - 41 = 8
Next number = 49 + 8 = 57
So, next cluster = Q V 57
Final Answer: QV57
Final Correct Option: (C)