Task: Question Answering
Input (English): Question: AT + CD = AAA, where AT and CD are two-digit numbers and AAA is a three digit number; A, T, C, and D are distinct positive integers. In the addition problem above, what is the value of C?

 Option A:  1

 Option B:  3

 Option C:  7

 Option D:  9

 Option E:  Cannot be determined
Output (English): Option D