In the sequence A, B, C, D, ?, F, what character should replace the question mark?

A. E

Identify the missing character in the series 1, 4, 9, ?, 25.

A. 16

Find the missing letter in the series M, N, O, ?, Q, R.

A. P

Find the missing letter in the sequence M, N, O, ?, Q, R.

A. P

If the pattern is 1, 2, 4, ?, 16, what number should replace the question mark?

B. 8