A very heavy box is kept on a frictionless incline plane inclined at an angle `theta` from the horizontal. Box is having an another frictionless incline plane, inclined plane as shown in the figure. A block of mass m is kept on this inclined plane inside the box. Acceleration of block w.r.t. box is

Options

A. `g sin^(2)theta`
B. `g cos^(2)theta`
C. `g sin thetacostheta`
D. zero

Explanation

`a_("box")=g sin theta`
`ma_(rel)=ma cos theta`
`rArra_(rel)=g sin theta cos theta`