Two initially identical samples A & B of pure germanium are doped with donors to concentrations of $$1 \times 10^{20}$$ and $$3 \times 10^{20}$$ respectively. If the hole concentration in A is $$9 \times 10^{12}$$ then the hole concentration in B at the same temperature will be

A

$$3 \times 10^{12} m^{-3}$$

B

$$7 \times 10^{12} m^{-3}$$

C

$$11 \times 10^{12} m^{-3}$$

D

$$27 \times 10^{12} m^{-3}$$