Select the number that can 11 the blank in the following number series.

5, 7, 6, 10, 7, 15, 8, ___, 9, 31, 10, 42

The series  contains two series according to separate patterns for odd and even terms:

1. Odd terms: 5, 6, 7, 8, 9,... This appears to be a simple increment by 1 series.
2. Even terms: 7, 10, 15,..., 31 The difference between consecutive terms seems to be increasing by 3, 5, 7, 9,...

So, let's continue this pattern:

1. Odd terms: 5, 6, 7, 8, 9,...
2. Even terms: 7, 10, 15, 22, 31,...

So, the next even term is 22. Therefore, the missing number is 22.

Option C is correct answer.