Answer the following question: Fact 1: The mass of an object causes the gravitational force exerted by that object. Fact 2: All gravitational forces are attractive, there is no repulsive gravitational force. Given the two facts above, the mass of an object causes the what exerted by that object?

Available choices:
(a). electromagnetic energy
(b). Electrical energy
(c). attractive force
(d). heat energy
(e). friction
(f). solid, liquid, gas
(g). energy of moving objects
(h). kinetic energy
Answer:
(c).