Which of the following is a DA receptor antagonist used for treating chemotherapy induced nausea and vomiting (CINV)?

Metoclopramide is recognized as a dopamine (DA) receptor antagonist, which specifically targets the D2 receptors in the central nervous system. Its primary use in the context of chemotherapy is for the prevention and treatment of chemotherapy-induced nausea and vomiting (CINV). By blocking dopamine receptors in the gastrointestinal tract and central nervous system, metoclopramide helps to reduce nausea and improve gastric motility, making it effective for patients undergoing chemotherapy.

Dronabinol, while used for treating nausea and vomiting, is primarily a cannabinoid and does not act as a DA receptor antagonist. Scopolamine is an anticholinergic agent that works by blocking acetylcholine, not dopamine receptors, and is typically used for motion sickness. Lorazepam is a benzodiazepine that can help with anxiety-related symptoms but does not have a direct mechanism of action as a DA receptor antagonist and is not primarily indicated for CINV. Thus, metoclopramide stands out as the appropriate choice in this context due to its specific action on dopamine receptors to alleviate nausea related to chemotherapy.