This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Platelet & Coagulation disorders, Subject name: Medicine
Which of the following drugs does not act by blocking GpIIb/IIIa receptors? 
Select and explain. 
A. Abciximab, B. Eptifibatide, C. Tirofiban, D. Clopidogrel
D: Clopidogrel
Answer: D: Clopidogrel 
Explanation: Clopidogrel inhibits ADP receptors whereas Abciximab, Tirofiban and Eptifibatide are GP IIb/IIIa antagonists.