A ball of mass `m` is rotating in a circle of radius `r` with speed `v` inside a smooth cone as shown in figure. Let `N` be the normal reaction on the ball by the cone, then choose the correct option:
A. `N=mg cos theta`
B. `g sin theta=(v^(2))/(r ) cos theta`
C. `N sin theta-(mv^(2))/(r )=0`
D. none of these