In the sequence P, Q, R, ?, T, U, what character is missing?

A. S

Teacher is to Teach as Doctor is to ?

A. HEAL

In the series: 1, 2, 4, 8, ?, 32, what is the missing number?

A. 16

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

A. Z

What is the missing character in the sequence: 3, 6, 9, ?, 15?

A. 12