What is the missing number in the series: 2, 6, 12, 20, ?, 42

B. 32

Find the missing number in the series: 5, 11, 23, 47, ?, 191

B. 93

What number should replace the question mark in the series: 1, 4, 9, 16, ?, 36

B. 25

Identify the missing number in the series: 3, 7, 13, 21, ?, 61

A. 31

What is the missing term in the series: 1, 2, 4, 8, ?, 32

B. 16