This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: General anatomy, Subject name: Anatomy
Vitamin used for post translational modification of glutamic acid to gamma carboxy glutamate is 
Select and explain. 
A. A, B. D, C. E, D. K
D: K
Answer: D: K 
Explanation: Ref Robbins 9/e p442 ,119. The vitamin K-dependent carboxylase carries out the posttranslational modification of specific glutamate residues in proteins togamma-carboxy glutamic acid (Gla) in the presence of reduced vitamin K, molecular oxygen, and carbon dioxide.