1.  13 29 15 26 17 23 19

A. 21 23
B. 20 21
C. 20 17
D. 25 27
E. 22 20

Answer: Option B

Explanation:

Here, there are two alternating patterns, with every other number following a different pattern. The first pattern begins with 13 and adds 2 to each number to arrive at the next; the alternating pattern begins with 29 and subtracts 3 each time.