Which of the following letter-number clusters will replace the question mark (?) NUB 63, JQX 54, FMT 45, BIP 36, XEL 27, ?

Observe the pattern in numbers:

63, 54, 45, 36, 27 → each time decreasing by 9
Next number = $27 - 9 = 18$

Now observe letters:

First letters: N, J, F, B, X → each step moves backward by 4 letters (cyclically)
Next first letter = T

Second letters: U, Q, M, I, E → each step moves backward by 4 letters
Next second letter = A

Third letters: B, X, T, P, L → each step moves backward by 4 letters
Next third letter = H

So the missing term is: TAH 18

Correct Answer: TAH 18