The width of a circular ring is equal to the radius of the inner circle of the ring if the radii of the inner and outer circle are r and R then the area of the circular ring is
A. 2πR2
B. 2πr2
C. 3πR2
D. 3πr2
The width of a circular ring is equal to the radius of the inner circle of the ring if the radii of the inner and outer circle are r and R then the area of the circular ring is
A. 2πR2
B. 2πr2
C. 3πR2
D. 3πr2