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
Non enveloped ss - RNA virus is: 
Select and explain. 
A. Picornavirus, B. Poxvirus, C. Retrovirus, D. Bunyavirus
A: Picornavirus
Answer: A: Picornavirus 
Explanation: Ans. is 'a' i.e., PicornavirusRNA Viruses (+ Stranded)Virus FamilyRNA StructureVirion - Associated PolymeraseEnvelopeShapeMultiplies inMajor VirusesCalicivirusss (+) RNA LinearNo polymeraseNakedIcosahedralCytoplasmNorwalk agent Noro -like virusHepesvirusss (+) RNA linearNo polymeraseNakedIcosahedralCytoplasmHepatitis EPicornavirusss (+) RNA LinearNo polymeraseNakedIcosahedralCytoplasmPolio**ECHOEnterovirusesRhinoCoxsackieHepatitis AFlavivirusss (+) RNA LinearNo polymeraseEnvelopedIcosahedralCytoplasmYello feverDengueSt. Louis encephalitisHepatitis CWest Nile virusTogavirusss (+) RNA LinearNo polymeraseEnvelopedIcosahedralCytoplasmRubellaWEE, EEEVenezuelan encephalitisCoronavirusss (+) LinearNo polymeraseEnvelopedHelicalCytoplasmCoronaviruses SARS - CoVRetrovirusDiploid ss (+) RNA LinearRNA dep. DNA polymeraseEnvelopedIcosahedral or truncated conicalNucleusHIVHTLVSarcomaMnemonic: (+) RNA Viruses: Call Henry Pico and Flo To Come Rightaway** Mnemonic: Picornaviruses: PEE Co Rn A VirusesPolio, Entero, Echo, Coxsackie, Rhino, Hep A