Correct option is A
Notice the pattern of the second letter:
• C (3rd letter of the alphabet)
• E (5th letter of the alphabet)
• G (7th letter of the alphabet)
• I (9th letter of the alphabet)
The second letters are increasing by 2 in their position in the alphabet: C (3), E (5), G (7), I (9)...
Following this pattern, the next letter should be:
• K (11th letter of the alphabet)
Thus, the next term in the series is K.