Correct Option: A

Poliomyelitis, often called polio or infantile paralysis, is an acute, viral, infectious disease spread from person to person, primarily via the fecal-oral route. The term derives from the Greek polios, meaning “grey”, myelos, referring to the grey matter of the spinal cord, and the suffix its which denotes inflammation., i.e., inflammation of the spinal cord’s grey matter, although a severe infection can extend into the brain stem and even higher structures, resulting in polio encephalitis, producing apnea that requires mechanical assistance such as an iron lung.