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
The odontoblasts killed during cavity preparation are derived from: 
Select and explain. 
A. Unaffected odontoblasts from the pulp, B. Undifferentiated cells, C. Histocytes, D. Osteoblasts
B: Undifferentiated cells
Answer: B: Undifferentiated cells 
Explanation: None