Assertion: Aristotle stated that an external force is required to keep a body in motion.
Reason: Opposing forces are always present in the natural world.
Options:
(a) Both A and R are true and R is the correct explanation of A.
(b) Both A and R are true but R is not the correct explanation of A.
(c) A is true but R is false.
(d) A is false and R is also false.