Answer:
The diseases are caused by viruses (option C)
Step-by-step explanation:
To begin with, antibacterial agents are groups of materials that are specifically used to disinfect surfaces as well as eliminate or kill bacteria that are potentially harmful.
Cold and flu are not caused by bacteria. As such, it would be inappropriate to use antibacterial agents to treat such diseases because they are viral infections (caused by virus). Thus, antiviral agents are appropriate for treating cold and flu.