A Block of Mass M Is Released from Rest at a Height

Multiple Choice

A block of mass m is released from rest at a height R above a horizontal surface. The acceleration due to gravity is g. The block slides along the inside of a frictionless circular hoop of radius R.
-What is the magnitude of the normal force exerted on the block by the hoop when the block reaches the bottom of the hoop?

A) zero newtons
B) mg²/R
C) mg
D) 2mg
E) 3mg