[单选题]
A block of mass M slides down a frictionless plane inub 53 ;pwqtekulksm6/2oe2:q dst a* 1clined at an angle 8,gpvwuu 4qvcp7u .n8 q with the horizontal. The normal reaction force exerted,7w u8vug4 pqcu8p.nv by the plane on the block is
A. $Mg$
B. $Mg \; \sin(q)$
C. $Mg \; \cos(q)$
D. zero, since the plane is frictionless.
