In a human, the aorta has a diameter of $36\text{ mm}$ as it leaves the heart. At this point, the wall of the aorta is $9\text{ mm}$ thick. What is the diameter of the lumen of the aorta at this point?
- A$1800\text{ m}$
- B$2700\,\mu\text{m}$
- C$18\,000\,\mu\text{m}$
- D$27\,000\,\mu\text{m}$