Complete the series: a, e, i, o, ?

A. U

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

B. 32

Identify the missing letters in the series: a, e, i, o, ?

A. U

Identify the missing letter in the series: a, e, i, o, ?

A. U

What is the next letter in the series: M, O, Q, S, ?

A. T