What number should replace the question mark in the series: 1, 2, 4, 8, 16, ?

B. 32

Complete the series: B, D, F, H, ?

A. J

Find the missing letter in the series: b, d, f, h, ?

A. J

A, C, E, G, ?

A. I

Find the missing letter in the series: z, x, v, t, ?

C. Q