A 58-year-old male with alcohol use disorder and multiple dental caries develops a pulmonary abscess (chest X-ray shows cavitary lesion with air-fluid level). He is started on clindamycin. Four days later, he presents with nausea, vomiting, and voluminous, profuse, green diarrhea. Vital signs: BP 118/76, HR 102, RR 18, Temp 38.2°C. Abdominal examination reveals diffuse tenderness without rebound. Stool culture is pending. Which antibiotic is most likely responsible for these symptoms?

1. A)Vancomycin
2. B)Chloramphenicol
3. C)ClindamycinGABARITO
4. D)Metronidazole
5. E)Gentamicin