Complete the series: 2, 5, 9, _____, 20, 27, 35.

None of these

The pattern in the series is adding 3, 4, 5, and so on:

2 + 3 = 5

5 + 4 = 9

9 + 5 = 14

14 + 6 = 20

20 + 7 = 27

27 + 8 = 35