The correct option is D NVOFMBS
Swapping the first and third letters in DESPAIR gives us: SEDPAIR
Now, swapping the fifth and seventh letters gives us: SEDPRIA
Now, replacing each letter with the alphabetically next letter gives us: TFEQSJB
Now, applying the same procedure on NUMERAL:
NUMERAL→MUNERAL→MUNELAR→NVOFMBS