Fact 1: Some viruses can cause cancer.

Fact 2: Lung cancer is a formation of tumors in the lung.

Given the two facts above, answer the question "Which is the most likely cause of throat tumors?" with the following options: 
- cigars
 - Allergies
 - viruses
 - Pesticides
 - rocks
 - doctors
 - the skin
 - water


 

   viruses      