4. Determine whether or not each of the following statements is true or false, and justify your answer with a proof or a counterexample. (a) (3 points) fr z dz = frdz, where I is the positively oriented unit circle |2| = 1. (b) (3 points) If f is analytic at every point on a closed contour T, then fr f(2) dz (c) (3 points) If f : S R is a real-valued function on a domain S c C, then the integral fr f(2) dz is a real number, for any contour I in S. = 0.