Complete the series: 10, 20, 40, 80, ?, 320.

A. 160

M, O, Q, S, ?

B. T

Complete the series: m, n, o, p, ?

A. Q

What letter comes next in the series: d, g, j, m, ?

A. P

What is the missing letter in the series: a, c, e, g, ?

B. H