Which statement about smallpox is true?

• A. Contagious and Infectious
• B. Non-Contagious
• C. Only Infectious
• D. Only Contagious

Answer: (A)

The main idea here is that some diseases are both infectious and contagious. Smallpox is caused by a virus, so it is an infectious disease—there is a pathogen that can cause illness. It is also contagious because it can spread from person to person through close contact, respiratory droplets, and contact with lesions or contaminated objects. That combination—being caused by a pathogen and spreading between people—makes the statement that smallpox is contagious and infectious the correct one. It isn’t non-contagious, and it isn’t limited to only one of those properties.