In the series A, B, C, D, E, F, G, how many letters are there before the letter D?

B. 3

If Z is the 26th letter, what is the 15th letter of the alphabet?

A. O

How many times does the letter 'A' appear in the series: A, B, A, C, A, D, E?

B. 3

In the series A, B, C, D, E, F, how many times does the letter 'E' appear?

A. 1

If the letter 'X' is the 24th letter of the alphabet, what is the letter that comes immediately before it?

A. W