<prompt> Please answer with one of the option in the bracket. Write reasoning in between . Write answer in between .Q:A 52-year-old woman complains of severe vomiting for the past 2 hours. She recently had a chemotherapy session for breast cancer. She denies a history of any relevant gastrointestinal diseases, including GERD. The physical exam does not demonstrate any epigastric or abdominal tenderness. The last bowel movement was yesterday and was normal. What is the primary mechanism of the drug which would be prescribed to treat her chief complaint?? A: D1 blocker, B: 5-HT2 blocker, C: 5-HT4 blocker, D: 5-HT1 blocker, E: 5-HT3 blocker,  <response>: This is a clinical vignette about a 52-year-old woman with severe vomiting after chemotherapy for breast cancer. The key details are:- Severe vomiting for 2 hours after chemotherapy - No history of gastrointestinal diseases like GERD- No abdominal tenderness on exam- Normal bowel movement yesterdayThe question asks about the primary mechanism of the drug that would be used to treat her vomiting. Based on the clinical scenario, this is most likely chemotherapy-induced nausea and vomiting CINV. The drug class that is first-line for treating acute CINV is 5-HT3 receptor antagonists blockers.E: 5-HT3 blocker 