**Core Concept**
Aspirin's mechanism of action involves irreversible inhibition of cyclooxygenase (COX) enzymes, specifically COX-1 and COX-2, which are responsible for the production of thromboxane A2 (TXA2) and prostaglandins. TXA2 is a potent vasoconstrictor that promotes platelet aggregation and blood clot formation. In patients undergoing surgery, the cessation of aspirin is crucial to minimize the risk of perioperative bleeding.

**Why the Correct Answer is Right**
Aspirin's effects on platelet aggregation can last for several days due to the irreversible inhibition of COX enzymes. The half-life of platelet turnover is approximately 7-10 days, which means that platelets produced before aspirin cessation will still be present in the circulation. Therefore, aspirin should be stopped at least 7-10 days prior to surgery to minimize the risk of bleeding. This allows for the production of new platelets that have not been exposed to aspirin and are less likely to be affected by its antiplatelet effects.

**Why Each Wrong Option is Incorrect**
**Option A:** 2 days - This is an insufficient duration to allow for the production of new platelets that have not been affected by aspirin.
**Option B:** 5 days - While this may be a safer duration than option A, it still may not be enough time for the majority of platelets to be replaced.
**Option C:** 14 days - This is an excessively long duration and is not necessary, as the antiplatelet effects of aspirin will have resolved by 7-10 days.

**Clinical Pearl / High-Yield Fact**
The timing of aspirin cessation varies depending on the type of surgery and the patient's individual risk factors for bleeding. A general guideline is to stop aspirin 7-10 days before elective surgery, but this may need to be adjusted based on the specific clinical scenario.

**Correct Answer: C. 14 days**