What is the missing term @ in the following? ACPQ : BESU : MNGI : @ NPJL NOJM NPIL NPJM

What is the missing term @ in the following

What is the missing term @ in the following?

ACPQ : BESU : MNGI : @

Answer: D

In such questions, you have to decipher the pattern in the first pair and then apply the same pattern in the second pair to find the answer.

The pattern has been depicted in the following diagram: