The diagram presents an enlarged view of a human liver cell, with a mitochondrion marked. The actual length of the liver cell is $20\,\mu\text{m}$. The image length of the liver cell is $40\,\text{mm}$ and the image length of the mitochondrion is $4\,\text{mm}$. What is the actual size of the mitochondrion shown in the diagram?
- A$0.002\,\text{mm}$
- B$0.02\,\text{mm}$
- C$0.2\,\text{mm}$
- D$2\,\text{mm}$