“C” is the next letter in the “A Z E B I Y O” series. Separating the series into three patterns reveals the explanation for this: vowels (A, E, I, O, U), letters backward (Z, Y, X,…), and consonants (B, C, D,…).
“A E I O” is the pattern of the vowels in the series. The backward letters follow the pattern ” Z Y .” Finally, the consonants are arranged in the form ” B .” It is clear from these independent patterns that the eighth letter in the series is neither a vowel nor a “X.” (not yet). As a result, it’s from the third series, the consonants, and “C” comes after “B.”