The diameter of a metal ring is `D` and the coefficient of linear expansion is `alpha`. If the temperature of the ring is increased by `1^(0)C`, the circumference and the area of the ring will increases by
A. `piDalpha, 2piDalpha`
B. `2piDalpha, piD^(2)alpha`
C. `piDalpha, (piDalpha)/2`
D. `piDalpha, (piD^(2)alpha)/(2)`
