Find the ODD one out from the given options.

Correct option is D

Option (a) DC:
D is the 4th letter of the alphabet, and C is the 3rd letter.
The difference between the positions of D and C is -1.
Option (b) CB:
C is the 3rd letter, and B is the 2nd letter.
The difference between C and B is -1.
Option (c) GF:
G is the 7th letter, and F is the 6th letter.
The difference between G and F is -1.
Option (d) EF:
E is the 5th letter, and F is the 6th letter.
The difference between E and F is +1.
All other options have a difference of -1, but option (d) EF has a difference of +1, which makes it the odd one out.
Correct answer is (d) EF.