SSC CGL 21-August-2017 Reasoning question 2

Select the related letters from the given alternatives.
DHL : AEI :: QUY : ?
Options:
1) MQU
2) NRV
3) OSW
4) PTX
Correct Answer: NRV
let A 1, b 2 and so on..

4 8 12 : 1 5 9 :: 17 21 25 :: ?
Gap of 3, So, fourth term will be 14 18 22 = N R V