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: Skin
In congenital dystrophic epidermolysis bullosa defect is seen in: 
Select and explain. 
A. Laminin 4, B. Collagen type 7, C. Collagen 4, D. Collagen 3
B: Collagen type 7
Answer: B: Collagen type 7 
Explanation: B. i.e. Collagen 7