A sketch of a human red blood cell is displayed. On the sketch, line XY measures $40\,\text{mm}$. The cell’s actual width is $0.008\,\text{mm}$. What is the magnification of the sketch?
- A$\times 500$
- B$\times 5000$
- C$\times 50\,000$
- D$\times 500\,000$