Suppose the gravitational force varies inversely as the `n^(th) `power of distance. Then the time period of a planet in circular orbit of radius R around the sun will be proportional to-
A. `R^(((n+1)/2))`
B. `R^(((n-1)/2))`
C. `R^(n)`
D. `R^(((n+2)/2))`
