A Block of Mass M Is Held Motionless on a Frictionless

Multiple Choice

A block of mass M is held motionless on a frictionless inclined plane by means of a string attached to a vertical wall as shown in the drawing.
-If the string breaks, what is the magnitude of the acceleration of the block as it slides down the inclined plane?

A) zero m/s²
B) g
C) g cos $\theta$
D) g sin $\theta$
E) g tan $\theta$