Which of the following terms will replace the question mark (?) in the given series ?

AVTE, CTRG, ERPI, GPNK, ?

INLM

Explanation:

AVTE, CTRG, ERPI, GPNK, ?

The logic followed here is :

A → (+2) → C → (+2) → E → (+2) → G → (+2) → I → (+2) 

V → (-2) → T → (-2) → R → (-2) → P → (-2) → N → (-2) 

T → (-2) → R → (-2) → P → (-2) → N → (-2) → L → (-2) 

E → (+2) → G → (+2) → I → (+2) → K → (+2) → M → (+2) 

So, the letter-cluster that replaces the (?) to complete the series is "INLM"