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
If a crack occurs in epoxy composite, some microcapsules rupture near the crack and releases dicyclopentadiene which subsequently fills the crack, this type of material is known as: 
Select and explain. 
A. Self-healing material., B. Self-assembling material., C. Smart materials., D. Bioactive materials.
A: Self-healing material.
Answer: A: Self-healing material. 
Explanation: It is an automatically initiated response to damage .