Identify the pattern: 1, 1, 2, 3, 5, 8, ?

D. 13

What comes next in the series: A1, B2, C3, D4, ?

A. E5

In the series 2, 4, 8, 16, what is the next number?

B. 32

What comes next in the series: Z, Y, X, W, ?

A. V

If the pattern is 5, 10, 20, 40, what is the next number?

C. 80