Question

norovirus is most commonly caused by:
improper handwashing
employees working while ill
improper cleaning of surfaces
not changing gloves between tasks

Explanation:

Norovirus is highly contagious. Employees working while ill can easily spread the virus as they may contaminate food, surfaces, etc. Improper handwashing, improper cleaning of surfaces, and not changing gloves between tasks can also contribute but employees working while ill is a major cause as they are a source of the virus in many settings like food - handling areas.

Answer:

Employees working while ill