**Core Concept**
Extrapyramidal symptoms (EPS) are a type of movement disorder caused by an imbalance of neurotransmitters in the basal ganglia. Dopamine blockade is a key mechanism underlying the development of EPS, particularly with antipsychotic medications and certain antiemetics.

**Why the Correct Answer is Right**
Metoclopramide is a dopamine antagonist that blocks D2 receptors in the nigrostriatal pathway, leading to EPS. This is because dopamine normally inhibits the release of acetylcholine in the striatum, and by blocking dopamine receptors, metoclopramide reduces this inhibitory effect, causing an increase in acetylcholine release and subsequent EPS. The risk of EPS is higher with metoclopramide due to its ability to cross the blood-brain barrier and directly affect central dopamine receptors.

**Why Each Wrong Option is Incorrect**
**Option B:** Domperidone is a dopamine antagonist, but it has a lower risk of EPS due to its limited ability to cross the blood-brain barrier, which reduces its central effects on dopamine receptors.

**Option C:** Prolactin is a hormone that is regulated by dopamine. Dopamine normally inhibits the release of prolactin from the pituitary gland. However, dopamine antagonists like metoclopramide can cause hyperprolactinemia by blocking dopamine receptors, but this is not directly related to the development of EPS.

**Option D:** This option is incorrect because not all of the above options are associated with EPS.

**Clinical Pearl / High-Yield Fact**
To remember the risk of EPS with dopamine antagonists, recall that "EPS" is an acronym for "Extrapyramidal Symptoms," but also note that "EPS" sounds like "Easy to Predict Side effects" when considering the effects of dopamine blockade on the basal ganglia.

**✓ Correct Answer: A. Metoclopramide**