Explanation:

- Each option represents a three-letter cluster of alphabetic sequences.

- Looking at the positions of these letters in the alphabet:

- Option 1: PVK

- P (16), V (22), K (11). Not in a direct sequence.

- Option 2: OUL

- O (15), U (21), L (12). Not in a direct sequence.

- Option 3: QUK

- Q (17), U (21), K (11). Not in a direct sequence.

- Option 4: MSN

- M (13), S (19), N (14). Sequence follows an arithmetic pattern (+6 and -5).

- All options except MSN do not follow a consistent arithmetic sequence.

- The odd one out is Option 4: MSN because it follows a pattern.

Correct Answer: Option 4: MSN