Read the following paragraphs, then answer the question on the right. After handling contaminated dog food, fourteen people in nine states became ill from salmonella. According to the Centers for Disease Control and Prevention (CDC), the people who got sick had given that same contaminated dog food to their pets. At least five people were taken to a hospital, but the incident did not affect any of their dogs.

When people handle contaminated pet food and do not wash their hands well before eating or handling food, they can become ill with salmonella.

The plant that made the dog food was closed while the issue was investigated. The same plant had made food that was recalled by the pet food company four different times in the previous five months. Upon reopening the plant, the company issued a statement that it had taken action to fix the problems.

The cause of the illness was?
A. Not washing hands
B. Salmonella on dog food
C. Unknown