Can you explain how to do this step by step in detail? For A I got C = 2pi r, but I don't know if that's the answer or not.

2. (a) Write the area A of a circle as a function of the circumference C. (b) Find the (instantaneous) rate of change of the area A with respect to the circumference C. (c) Evaluate the rate of change of A at C = 17 and C = 617. (d) If C is measured in inches and A is measured in square inches, what units would be appropriate for dA/dC