Four letter-clusters have been given, out of which three are alike in some manner and one is different. Select the odd letter-cluster.

The correct answer is HJKP.

To find the odd one out, we assign each letter its position number in the English alphabet (A=1, B=2, C=3, … Z=26) and look for a pattern in the differences between consecutive letters within each cluster.

Cluster 1: BFJN
B = 2, F = 6, J = 10, N = 14
Differences: 6-2 = 4, 10-6 = 4, 14-10 = 4
→ Each letter increases by +4. Pattern holds ✓

Cluster 2: DHLP
D = 4, H = 8, L = 12, P = 16
Differences: 8-4 = 4, 12-8 = 4, 16-12 = 4
→ Each letter increases by +4. Pattern holds ✓

Cluster 3: JNRV
J = 10, N = 14, R = 18, V = 22
Differences: 14-10 = 4, 18-14 = 4, 22-18 = 4
→ Each letter increases by +4. Pattern holds ✓

Cluster 4: HJKP
H = 8, J = 10, K = 11, P = 16
Differences: 10-8 = 2, 11-10 = 1, 16-11 = 5
→ The differences are inconsistent (2, 1, 5). Pattern does NOT hold ✗

Conclusion: Three clusters — BFJN, DHLP, and JNRV — all follow the same rule: each successive letter is exactly 4 positions ahead of the previous one. HJKP breaks this rule entirely with irregular gaps of 2, 1, and 5, making it the odd one out.