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

A. P

In the series X, Y, ?, A, B, what character is missing?

A. Z

In the pattern P, Q, R, ?, T, U, which character is missing?

A. S

In the series: 1, 4, 9, ?, 25, what number should replace the question mark?

A. 16

Identify the missing letter in the pattern: X, Y, ?, A, B.

A. Z