This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Dental
A cross-section of the cervical third of the pulp canal of a maxillary second premolar resembles in shape: 
Select and explain. 
A. A circle, B. A square, C. A triangle, D. An ellipse
D: An ellipse
Answer: D: An ellipse 
Explanation: None