This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Metabolic Bone Disease, Subject name: Orthopaedics
Osteogenesis imperfect has abnormality in which type of collagen - 
Select and explain. 
A. Collagen 3, B. Collagen 2, C. Collagen 4, D. Collagen 1
D: Collagen 1
Answer: D: Collagen 1 
Explanation: Ans. is 'd' i.e., Collagen 1