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
When using the acid etch technique to restore a Class IV
fracture, exposed dentin should first be covered with: 
Select and explain. 
A. Cavity varnish, B. Phosphoric acid, C. A calcium hydroxide liner, D. Zinc oxide-eugenol cement
C: A calcium hydroxide liner
Answer: C: A calcium hydroxide liner 
Explanation: None