Identify the missing letter in the series: m, n, o, ?, q, r

A. P

What is the next number in the series: 7, 14, 28, 56, ?

B. 112

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

B. H

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

B. H

What number should come next in the series: 10, 20, 30, 40, ?

B. 50