Select the option that is related to the third term in the same way as the first term is related to the second term.
DFIM : WURN :: CMHV: ........

Let us decode the relationship between DFIM and WURN

D is the 4th alphabet from the start in the English alphabetical sequence and W is the 4th alphabet from the end in the alphabetical order.

D - W

similarly, 

F- 6th alphabet from the beginning, 

and 

U- 6th alphabet from the end.

DF-WU

I- 9th alphabet from the beginning

and 

R- 9th alphabet from the end.

DFI-WUR

M-13th alphabet from the beginning

and

N-13th alphabet from the end

DFIM- WURN

Establishing the same relationship for CMHV

C- 3rd from beginning

X- 3rd from the end.

C-X

M-13th from the beginning

N- 13th from the end.

CM-XN

H-8th from the beginning,

S-8th from the end

CMH-XNS

V-21st from the beginning

E- 21st from the end .

CMHV-XNSE

Hence the right answer is option A