Correct Option: A

Mumps (epidemic parotitis) is a viral disease of the human species, caused by the mumps virus. Before the development of vaccination and the introduction of a vaccine, it was a common childhood disease worldwide. It is still a significant threat to health in the third world, and outbreaks still occur sporadically in developed countries. Painful swelling of the salivary glands (classically the parotid gland) is the most typical presentation..