Find the missing number in the series: 5, 10, 20, 40, ?

D. 80

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

B. 25

Identify the missing number in the series: 2, 5, 10, 17, ?

B. 25

What is the missing number in the series: 2, 4, 8, 16, ?, 64?

A. 32

Find the missing number in the series: 5, 10, 20, 40, ?

C. 80