Find the missing character in the series A1, B2, C3, ?, E5.

A. D4

In the sequence P, Q, R, S, ?, U, V, which character is missing?

A. T

In the pattern 5, 10, 15, ?, 25, what number is missing?

A. 20

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

B. 12

Find the missing character in the pattern: X, Y, Z, ?, B.

A. A