A solid hemisphere and a solid cone have a common base and are made of same material. The centre of mass of the common structure coincides with the centre of the common base. If R is the radius of hemisphere and h is height of the cone, then
A. `(h)/(R )=sqrt(3)`
B. `(h)/(R )=(1)/sqrt(3)`
C. `(h)/(R )=3`
D. `(h)/(R )=(1)/(3)`