A small block of mass `M` moves on a frictionless surface of an inclined plane, as shown in the figure. The angle of the incline suddenly changes from `60^(@)` to `30^(@)` at point `B`. The block is many at rest at `A`. Assume that collisions between the block id the incline are totally inelastic.
The speed of the block at point `C`, immediately before it leaves the second incline

Options

A. `sqrt(120)` m/s
B. `sqrt(105)` m/s
C. `sqrt(90)` m/s
D. `sqrt(75)` m/s

Answer

B