Teacher Chen wrote the name of one of the four students A. B, C, and D with a pen in his hand. Then he clenched his hands and let the four people with A. B, and C guess the name of the person he wrote. A said, "It is C "B said," Not my name. "C said," Not my name. "D said," It is A. "Teacher Chen said," Only one of you four guessed right. ". Which classmate did Mr. Chen write? ['Classmate A.', 'Classmate B.', 'Class C.', 'Ding.']