Choose the odd one out.

The answer is D. QN.

The other options, A, B, C, and E, all have two letters that are the same. For example, in GE, both the first and second letters are E. In MK, both the first and second letters are M. In WU, both the first and second letters are W. In OU, both the first and second letters are O.

However, in QN, the first letter is Q and the second letter is N. These two letters are not the same. Therefore, QN is the odd one out.