[单选题]
The volume of the Ea0/)b4m8s4fo t0swjxc)rp eu a pno-blup0h-c,q+d -t s f-k(qrth is approximately $10^{12} \mathrm{~km}^3$ and the volume of a grain of sand is approximately $1 \mathrm{~mm}^3$. To the nearest order of magnitude, if the Earth was hollow, how many grains of sand could it contain?
A. $10^{12}$
B. $10^{18}$
C. $10^{24}$
D. $10^{30}$
Post time 2024-8-21 21:17:15