Given a circle C of radius 1 centered at (0, 0, 1) on the plane z = 1. (a) Find a parametrization for the circle C. (b) Evaluate the line integral of the vector field F~ (x, y, z) = h-y, x, z^2 i from (1, 0, 1) to (-1, 0, 1), along the circle C, oriented counterclockwise when viewed from above.