Select the letter-pair that can replace the question mark (?) in the following series.
KP, HM, EJ, BG, ?
Answer & explanation
Correct answer: option 2

Explanation:
KP, HM, EJ, BG, ?
The logic followed here is :
K → (-3) → H → (-3) → E → (-3) → B → (-3) → Y
P → (-3) → M → (-3) → J → (-3) → G → (-3) → D
So, the letter-cluster that replaces the (?) to complete the series is "YD"