Number Series - Verbal and Reasoning

Directions to SolveLook carefully for the pattern, and then choose which pair of numbers comes next.
Q1:

9 12 11 14 13 16 15

A 14 13

B 18 21

C 14 17

D 12 13

E 18 17

ANS:E - 18 17

This is a simple alternating addition and subtraction series. First, 3 is added, then 1 is subtracted, then 3 is added, 1 subtracted, and so on.