A client with a diagnosis of cancer is scheduled for chemotherapy. The nurse anticipates administering which of the following medications, 30-60 minutes prior to chemotherapy treatment?

A. Scopolamine.: Scopolamine is an anticholinergic primarily used to prevent motion sickness or postoperative nausea related to anesthesia. It is not the preferred agent for chemotherapy-induced nausea and vomiting because it does not target serotonin receptors involved in chemotherapy-related emesis. B. Metoclopramide.: Metoclopramide is a prokinetic and antiemetic that enhances gastric motility and is sometimes used for mild to moderate nausea. However, it is less effective against the severe nausea caused by chemotherapy and may cause extrapyramidal side effects C. Methylcellulose.: Methylcellulose is a bulk-forming laxative used to treat constipation by increasing stool volume and water content. It has no antiemetic properties and would not be useful in preventing chemotherapy-related nausea or vomiting. D. Ondansetron.: Ondansetron is a serotonin 5-HT3 receptor antagonist that effectively prevents chemotherapy-induced nausea and vomiting. Administering it 30–60 minutes before treatment blocks serotonin release from the gastrointestinal tract, reducing nausea severity.