A small block of mass m is kept on a rough inclined surface of inclination `theta` fixed in an elevator. The elevator goes up with a uniform velocity v and te block does not slide n te wedge. The work done by the force of friction on the block in time t will be
A. Zero
B. mgvt `cos^(2)theta`
C. mgvt `sin^(2)theta`
D. mgvt `sin 2theta`
