In parallelogram A B C D, AD = 9 and A B = 6. Find m \angle A D C.
Choices:
A:42
B:52
C:72
D:128
Please directly answer the question and provide the correct option letter, e.g., A, B, C, D.
Question: In parallelogram A B C D, AD = 9 and A B = 6. Find m \angle A D C.
Choices:
A:42
B:52
C:72
D:128
Please first conduct reasoning, and then answer the question and provide the correct option letter, e.g., A, B, C, D, at the end.
Question: In parallelogram A B C D, AD = 9 and A B = 6. Find m \angle A D C.
Choices:
A:42
B:52
C:72
D:128