[单选题]
A block of mass M slides down a frictioldq6w ze/* v;+ve z9wvnless plane inclined at an angl q*k1 mi(i-lgze q with the horizontal. Thl- m*ki(gz q1ie normal reaction force exerted by the plane on the block is
A. $Mg$
B. $Mg \; \sin(q)$
C. $Mg \; \cos(q)$
D. zero, since the plane is frictionless.
