A block is pulled at constant speed along a rough level surface by a rope that makes an angle of 30o with respect to the horizontal. The applied force along the rope is P. the force of kinetic friction between the block and the surface is 10N.

Complete the following statement. The magnitude of the normal force could be reduced by

A. increasing the speed of the block

B. decreasing the coefficient of kinetic friction

C. decreasing the velocity of the block

D.decreasing the angle made by the rope

E. increasing the angle made by the rope