[单选题]
A block of mass M slides down a frictionless plane inchl cagpy*2(9qewzbi 7 kmy;8 ;li2mogm4d iu :v.ned at an angle q with the horizontal. The normal reaction force exerted vm :dmou 4i2g.by the plane on the block is
A. $Mg$
B. $Mg \; \sin(q)$
C. $Mg \; \cos(q)$
D. zero, since the plane is frictionless.
