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

A. I

A, C, E, G, ?

A. I

Find the odd one out in the series: A, C, E, G, I, K, M, O, Q, R

D. R

A, E, I, M, ?

B. O

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

B. S