AIDS (caused by HIV), mumps, and poliomyelitis are all viral diseases. AIDS is caused by the Human Immunodeficiency Virus (HIV), mumps by the mumps virus, and polio by poliovirus. This distinguishes them from bacterial, fungal, or parasitic diseases. While option D has some truth for AIDS (blood transmission can spread HIV), it doesn't apply to mumps or polio, making option C the unifying characteristic.