(A) :A body can have acceleration even if its velocity is zero at a given instant of time.
(R) : A body is momentarily at rest when it reverses its direction of motion.

According to the question, 

The velocity of the body is thrown vertically up and is zero at its highest point whereas the acceleration of the body continues to act in the diwnward direction. so at the instant, body has acceleration while its velocity is zero. also at the highest point the body reverses its direction hence,the body will be rest when it reverses its direction of motion.