Assertion (A) Work done by friction on a body sliding down an inclined plane is positive.
Reason (R) Work done is greater than zero it the angle between force and displacement is acute.

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, but R is true

Answer: Option D