Which surface in three-dimensional space is described by the relation 0=/ in cylindrical coordinates? O a. A plane with normal vector (0, 1, 0) . O b. The x - z plane. O c. A half-plane with normal vector (0, It/2, 0) . O d. The x - y plane.Which surface in three-dimensional space is described by the relation = in spherical coordinates? O a. A ray starting from the origin. O b. A quarter of a disk. O c. The x - z plane. O d. The x - y plane