Sis the set of prime numbers that are less than 15 a. {2, 3, 5, 7, 11, 13} b.{2, 3, 5, 7, 9, 11, 13} c.{1, 3, 5, 7, 9, 11, 13} d.{1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15}

Use stokes' theorem to evaluate c f · dr where c is oriented counterclockwise as viewed from above. f(x, y, z) = xyi + 5zj + 7yk, c is the curve of intersection of the plane x + z = 8 and the cylinder x2 + y2 = 81.