**Core Concept**
Aspirin, being a nonsteroidal anti-inflammatory drug (NSAID), inhibits cyclooxygenase (COX) enzymes, which are crucial for the production of thromboxane A2. Thromboxane A2 is a potent vasoconstrictor and promotes platelet aggregation. By inhibiting COX enzymes, aspirin reduces the production of thromboxane A2.

**Why the Correct Answer is Right**
The correct answer is related to the effect of aspirin on the production of thromboxane A2. Aspirin inhibits COX-1 and COX-2 enzymes, leading to a decrease in thromboxane A2 production. This decrease in thromboxane A2 results in a reduction in platelet aggregation and vasoconstriction. The reduction in platelet aggregation is the primary mechanism by which aspirin exerts its antiplatelet effects.

**Why Each Wrong Option is Incorrect**
**Option A:** This option is incorrect as it does not relate to the effect of aspirin on platelet aggregation or thromboxane A2 production. The effect of aspirin on prostaglandin production is indirect, as prostaglandins are not directly involved in platelet aggregation.

**Option B:** This option is incorrect as it is not directly related to the effect of aspirin on thromboxane A2 production. The production of leukotrienes is not directly affected by aspirin.

**Option C:** This option is incorrect as it is not a direct consequence of aspirin's effect on thromboxane A2 production. The effect of aspirin on blood pressure is complex and involves multiple mechanisms, including the inhibition of prostaglandin production.

**Clinical Pearl / High-Yield Fact**
Aspirin's antiplatelet effects are primarily due to its inhibition of COX-1 enzymes, which are responsible for the production of thromboxane A2. This effect is reversible with platelet turnover, which occurs every 7-10 days.

**Correct Answer: D.**