This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Virology, Subject name: Microbiology
[{'content': 'Viroids are ? \nSelect and explain. \nA. ssRNA, B. DNA from matric proteins, C. Naked pathogenic human viruses, D. Fragments of viruses', 'role': 'user'}, {'content': 'Answer: A \nExplanation: Genome much smaller than those of known virus. Agent is a protien free low molecular wt RNA REF:ANANTHANARYANAN TEXT BOOK OF MICROBIOLOGY 9EDITION PDNO.442', 'role': 'assistant'}]