Which of the following letter-number clusters will replace the question mark (?) in the given series to make it logically complete?
LDH 14, NFJ 17, PHL 20, RJN 23, ?

Correct option is A

Given: LDH 14, NFJ 17, PHL 20, RJN 23, ?
Logic: Each letter increased by +2 places n English alphabet and number increased by +3

1st letter:
L + 2 = N
N + 2 = P
P + 2 = R
R + 2 = T​
2nd Letter:
D + 2 = F
F + 2 = H
H + 2 = J
J + 2 = L
3rd Letter:
H + 2 = J 
J + 2 = L
L + 2 = N
N + 2 = P
Number:
14 → 17 → 20 → 23 → 26
So, ? = TLP 26
Thus, the correct option is (A) TLP 26