If viruses are not living, how do they cause disease?

In an episode of the classic 1950s television comedy The Honeymooners, Brooklyn bus driver Ralph Kramden loudly explains to his wife, Alice, “You know that I know how easy you get the virus.” Half a century ago even regular folks like the Kramdens had some knowledge of viruses—as microscopic bringers of disease. Yet it is almost certain that they did not know exactly what a virus was. They were, and are, not alone.

Explanation:

its in the answer

answer; i believe the correct answer is (a)0