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

A. D

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

A. 8

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

A. Z

What character should replace the question mark in the sequence 3, 6, 9, ?, 15?

B. 12

If M + N means M is the sister of N, and N * O means N is the mother of O, what is the relationship between M and O?

B. AUNT