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: Pharmacology
Clopidogrel inhibit platelet aggregation by : 
Select and explain. 
A. Inhibit Gp IIb/IIIa, B. Inhibits phosphodiesterase, C. Inhibits ADP, D. Inhibits cyclooxygenase
C: Inhibits ADP
Answer: C: Inhibits ADP 
Explanation: None