To solve this problem, we need to identify which virus shows a coiled RNA strand and capsomeres.$\newline$Let's analyze the given options:$\newline$• Option 1: Polio virus - This virus has an icosahedral structure with a single-stranded RNA, but it does not have a coiled RNA strand.$\newline$• Option 2: Tobacco mosaic virus (TMV) - This virus is known for its helical structure, where the RNA is coiled within a protein coat made of capsomeres.$\newline$• Option 3: Measles virus - This virus has a helical nucleocapsid, but it is not typically described with a coiled RNA strand and capsomeres in the same context as TMV.$\newline$• Option 4: Retrovirus - These viruses have a complex structure with RNA, but they are not characterized by a coiled RNA strand and capsomeres.$\newline$The Tobacco mosaic virus (TMV) is the classic example of a virus with a coiled RNA strand and capsomeres.$\newline$Therefore, the correct option is Option 2.