Which of the Following Statements Concerning Negative Feedback Is Incorrect

Which of the following statements concerning negative feedback is incorrect?

A) negative feedback exists when a change in a regulated variable triggers a response that opposes the change.
B) negative feedback exists when the input to a system increases the output and the output limits its own production by inhibiting the input.
C) with negative feedback, a control system's input and output continue to enhance each other.
D) most of the body's homeostatic control mechanisms operate on the principle of negative feedback.
E) it is the only mode of extrinsic control.