Identify the missing letter in the pattern: A, C, E, ?, I.

A. G

PEN is to WRITE as BRUSH is to ?

B. PAINT

In a series of letters: M, O, Q, S, ?, Y. What is the missing letter?

A. T

What character completes the pattern: X, Y, Z, A, B, ?

A. C

Identify the missing character in the series 1, 4, 9, ?, 25, 36.

A. 16