[单选题]
A parallel-plate capacitor is co-ob /it x,j-alnstructed with plate a1 ff(f-jn2z dhrea of $0.40 \; m^{2}$ and a plate separation of 0.10 mm. How much charge is stored on it when it is charged to a potential difference of 12 V?
A. $0.21 \; mC$
B. $0.42 \; mC$
C. $0.63 \; mC$
D. $0.84 \; mC$
