The answer is C. influenza, chicken pox, and colds because influenza, chicken pox, and colds (called rhinovirus) are all caused by viruses. Food poisoning is not a virus, athlete's foot is a fungal infection, and strep throat is a bacterial infection.
If i remember correctly it should be your doctor
If you're meaning like to check if someone's respiratory system is working right you'd want to find a pulse. If you find there's no pulse you should start chest compressions and call 911 continuing to do chest compressions
