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: Pathology
True regarding blood coagulation is 
Select and explain. 
A. Addition of Vitamin-K to the freshly drawn blood sample delays clotting, B. Thrombin conves fibrin to fibrinogen, C. Heparin inhibits blood coagulation by interfering with Vitamin K metabolism in the liver, D. Platelet is essential for blood clot formation
D: Platelet is essential for blood clot formation
Answer: D: Platelet is essential for blood clot formation 
Explanation: . Platelet is essential for blood clot formation