**Core Concept**
Antiplatelet drugs are a class of medications that prevent platelet activation and aggregation, thereby reducing the risk of thrombus formation. These drugs are commonly used in patients with cardiovascular disease, such as those with a history of myocardial infarction or stroke.

**Why the Correct Answer is Right**
The correct answer is an antiplatelet drug that works by inhibiting the binding of fibrinogen to the glycoprotein IIb/IIIa receptor on platelets, thereby preventing platelet aggregation. This drug is a type of P2Y12 receptor antagonist.

**Why Each Wrong Option is Incorrect**
**Option A:** This is an incorrect statement as this option is indeed an antiplatelet drug. It works by inhibiting the binding of adenosine diphosphate (ADP) to the P2Y12 receptor on platelets, thereby preventing platelet aggregation.
**Option B:** This is an incorrect statement as this option is indeed an antiplatelet drug. It works by inhibiting the enzyme cyclooxygenase-1 (COX-1), which is responsible for the production of thromboxane A2, a potent stimulator of platelet aggregation.
**Option C:** This is the correct answer as it is not an antiplatelet drug. It is actually an anticoagulant that works by inhibiting the synthesis of vitamin K-dependent clotting factors in the liver.

**Clinical Pearl / High-Yield Fact**
It's essential to remember that antiplatelet drugs can increase the risk of bleeding, especially in patients with a history of gastrointestinal bleeding or those taking other anticoagulant medications.

**Correct Answer:** C. Heparin.