Correct Answer - Option 2 : 10
Given series: 2, A, 9, B, 6, C, 13, D, ?
There are two series, one is of numbers and other is of letters.
Number series: 2, 9, 6, 13, ?
Letter series: A, B, C, D
2 + 7 = 9
9 - 3 = 6
6 + 7 = 13
13 - 3 = 10
Hence, 10 is the correct. answer