[单选题]
The mass of an electrokzef n.sc exd//;7zq 9n i4snm x8sguxcwh 9:8j06e3h wh s $9.1 \times 10^{-31} \; kg$. How many electrons will make a mass of 1.0 kg?
A. $9.1 \times 10^{30}$
B. $1.1 \times 10^{30}$
C. $9.1 \times 10^{31}$
D. $1.1 \times 10^{31}$
