<prompt> Please answer with one of the option in the bracket. Write reasoning in between . Write answer in between .Q:A 60-year-old man comes to the physician for the evaluation of nausea over the past week. During this period, he has also had several episodes of non-bloody vomiting. Last month, he was diagnosed with stage II Hodgkin lymphoma and was started on adriamycin, bleomycin, vinblastine, and dacarbazine. His temperature is 37C 98.6F, pulse is 95min, and blood pressure is 10570 mm Hg. Physical examination shows cervical lymphadenopathy. The liver is palpated 1 to 2 cm below the right costal margin, and the spleen is palpated 2 to 3 cm below the left costal margin. The remainder of the examination shows no abnormalities. The patient is started on an appropriate medication. Two weeks later, he develops headaches and states that his last bowel movement was 4 days ago. The patient was most likely treated with which of the following medications?? A: M2 antagonist, B: Cannabinoid receptor agonist, C: H1 antagonist, D: D2 antagonist, E: 5-HT3 antagonist,  <response>: This is a clinical vignette about a 60-year-old man with nausea and vomiting likely related to chemotherapy for Hodgkin lymphoma. He is started on an appropriate medication to treat the nausea and vomiting, and later develops constipation and headaches. The key points are:- Nausea and vomiting are common side effects of chemotherapy- The patient has enlarged lymph nodes, liver, and spleen, suggesting lymphoma - An antiemetic medication is started to treat the nausea and vomiting- The patient later develops constipation and headaches, which are side effects of some antiemeticsBased on this information, the most likely medication started is a 5-HT3 antagonist like ondansetron or granisetron. These drugs are commonly used to prevent chemotherapy-induced nausea and vomiting. Constipation and headache are common side effects.E: 5-HT3 antagonist 