A uniform cylinder of mass M and radius R is to be pulled over a step of height a `(a lt R)` by applying a force F at its centre O perpendicular to the plane through the axes of the cylinder on the edge of the step (see figure ) . The minimum value of F required is :

Options

A. `Mg (a)/(R)`
B. `Mgsqrt((R/(R-a))^(2)-1)`
C. `Mg sqrt(1-a^(2)/R^2)`
D. ` Mgsqrt(1-((R-a)/(R))^2)`