What letter comes next in the series: z, x, v, t, ?

A. S

Identify the missing letter in the series: a, e, i, o, ?

A. U

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

A. Q

What is the next letter in the series: A, C, E, G, ?

A. I

Identify the missing letter in the series: Z, X, V, T, ?

D. P