This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Dental
[{'content': 'All the following drugs are effective in t/t of ptyriasis versicolor except – \nSelect and explain. \nA. Selenium sulphide, B. Ketoconazole, C. Grieseofulvin, D. Clotrimazole', 'role': 'user'}, {'content': 'Answer: C \nExplanation: Griseofulvin is effective only against dermatophytes. It is ineffective against T. versicolor and candida.', 'role': 'assistant'}]