A Block of Mass M Slides Down a Frictionless Plane

Multiple Choice

A block of mass M slides down a frictionless plane inclined at an angle θ with the horizontal. The gravitational force is directed

A) parallel to the plane in the same direction as the movement of the block.
B) parallel to the plane in the opposite direction as the movement of the block
C) perpendicular to the plane.
D) toward the center of the Earth.
E) an angle θ below the inclined plane.