Consider the vector field f = (y-x, x) and curve c: r(t) = (5cos t, 5sin 0 for 0 lessthanorequalto t lessthanorequalto2 pi. a. based on the picture, make a conjecture about whether the circulation of f on c is positive, negative, or zero. b. compute the circulation. a. choose the best answer below. a. the circulation is probably positive because the vector field resembles a clockwise rotation field. the circulation is probably positive because the vector field resembles a counterclockwise rotation field. the circulation is probably close to zero because the vector field is nearly symmetric across a line that passes through the center of the circle. b. the circulation is: (type an exact answer, using x as needed.)