A point on the rim of a flywheel has a peripheral speed of 10 `ms^(-1)` at an instant when it is decreasing at the rate of `60ms^(-1)`. If the magnitude of the total acceleration of the point at this instant is `100ms^(-2)`, the radius of the flywheel is
A. `1.25m`
B. `12.5m`
C. `25m`
D. `2.5m`