Explanation:

- Option 1: RUXA

- Letters are in increasing gaps: R-S-T-U, U-V-W-X, X-Y-Z-A.

- Option 2: MPSV

- Letters have increasing gaps between them: M-N-O-P, P-Q-R-S, S-T-U-V.

- Option 3: BEHK

- Letters follow a pattern with 1, 2, and 3 position increments: B-C-D-E, E-F-G-H, H-I-J-K.

- Option 4: GJMQ

- Each letter sequence increases by consistent intervals: G-H-I-J, J-K-L-M, M-N-O-P, each with +3.

Option 4 is different because it has consistent +3 intervals between each letter in sequence. The others increase their intervals progressively. GJMQ is the odd cluster.