In a series of numbers: 2, 4, 8, 16, ?, 64. What is the missing number?

B. 32

In the series X, Y, Z, A, ?, C, D, what character should fill the gap?

A. B

In the sequence P, Q, R, S, ?, U, V, which character is missing?

A. T

In the series X, Y, Z, A, ?, C, D, which letter should fill the gap?

A. B

In a sequence of letters: A, C, E, G, ?, K. What is the missing letter?

B. H