Explanation:

Identifying the correct option:
The correct answer is option 'C' because it is the only option that correctly follows the pattern of the given series.

Pattern in the series:
- The series is a combination of letters and numbers.
- Each letter is followed by the square of the position of that letter in the English alphabet.
- For example, A is the first letter, so it is followed by 1 (1^2), B is the second letter, so it is followed by 4 (2^2), and so on.

Breaking down the options:
a) A1, B4, C9, D16 - This option follows the pattern of the series, but it starts with the wrong letter (A instead of B).
b) A1, C4, E9, G16 - This option does not follow the pattern of the series as it skips alternate letters and does not follow the square of the position of the letters.
c) A1, B4, D9, G16 - This option is the correct answer as it follows the pattern of the series by correctly squaring the position of each letter.
d) A1, C4, F9, J16 - This option does not follow the pattern of the series as it incorrectly assigns squares of the positions of the letters.

Therefore, option 'C' (A1, B4, D9, G16) is the correct answer as it correctly follows the pattern of the given series.