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: Medicine
A 50 years old female on junk food diet presented with point hemorrhages in scalp, bleeding in joints and erythemataous lesions in the skin. X-ray of knee joint was suggestive of hemahrosis. Problem lies with: 
Select and explain. 
A. Hydroxylation of proline and lysine, B. Carboxylation of glutamic acid, C. Carboxylation of coagulation factors, D. Platelet aggregation defect
A: Hydroxylation of proline and lysine
Answer: A: Hydroxylation of proline and lysine 
Explanation: Answer- A. Hydroxylation of proline and lysineVitamin C is required for post-translational modification of lysine and proline in collagen synthesisHydroxyproline is formed by post-translational hydroxylation catalyzed by prolyl hydroxylase, whose cofactors are ascorbic acid and Keto- alpha glutarate.