In the Figure,a Force F Is Being Applied to the Block

Multiple Choice

In the figure,a force F is being applied to the block with a magnitude such that it moves up along the frictionless inclined place with a constant velocity of 5 m/s.The angle in the figure is 30 ^$\circ$ ,and the mass of the block is 50 kg.What is the normal force exerted by the inclined plane on the block (within 5% accuracy) ?

A) 50 N
B) 240 N
C) 425 N
D) 500 N
E) zero