Select the letter that can replace the question mark (?) in the following series.
C, A, E, C, G ?

Correct option is C

Given: C, A, E, C, G ?
Now, observe the differences between consecutive letters:
C (3) → A (1): Decrease by 2
A (1) → E (5): Increase by 4
E (5) → C (3): Decrease by 2
C (3) → G (7): Increase by 4
The pattern alternates between decreasing by 2 and increasing by 4.
Following this logic:
G (7) → ? (7 - 2): The next letter should be E.
So, the correct answer is (c) E.