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: Pathology
Epidermolysis bullosa occurs due to alteration is structure of which of the following collagen: 
Select and explain. 
A. Type 1 collagen., B. Type 4 collagen., C. Type 6 collagen., D. Type 7 collagen.
D: Type 7 collagen.
Answer: D: Type 7 collagen. 
Explanation: None