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: Physiology
Primary cause of bleeding disorder in liver damage is due to 
Select and explain. 
A. decreased level of prothrombin, B. Lack of vitamin K, C. Platelet deficiency, D. Lack of vitamin B
A: decreased level of prothrombin
Answer: A: decreased level of prothrombin 
Explanation: None