4. Background Story: Verify the Green's theorem for F(x, y) = (xy, x-y) over the region D whose boundary is the rectangle with vertices (0, 0), (7,0), (7,4), (0, 4) by following answering Items (A)-(D). (0, 4) 1 (7, 4) CA D C2 (0, 0) (7, 0) Question (s): (A) (1 point) Parameterize each line segment. C1: F, (t) the line segment from (0, 0) to (7, 0), C2: F2(t) the line segment from (7, 0) to (7, 4), C3: F3(t) the line segment from (7, 4) to (0, 4), and CA: FA(t) the line segment from (0, 4) to (0, 0). (As shown in the picture.) 6 (B) (2 points) Compute each / F . de. F . de. F . dr and / F . de. (C) (0.5 points) Let C = C UC2 UC3 UCA. Use Part (B) to compute OF . dr. (D) (0.5 points) Compute curl(F) dA