Choose the odd one.
A2011
B2012
C2013
D2014
A2011
B2012
C2013
D2014
Related Questions:
Based on the English alphabetical order, three of the following four letter-clusters are alike in a certain way and thus form a group. Which letter-cluster DOES NOT belong to that group?
(Note: The odd one out is not based on the number of consonants/vowels or their position in the letter-cluster.)