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
Anatomic form of roots of teeth is determined by 
Select and explain. 
A. Dental lamina, B. Neural crest cells, C. Hertwig's root sheath, D. Hammock ligament
C: Hertwig's root sheath
Answer: C: Hertwig's root sheath 
Explanation: None