Staphyloccocus aureus is a gram-positive bacteria which is responsible for various infection in humans. 15 to 40 % of normal humans contain staphylococcus aureus in their nose and on their skin therefore you should learn to avoid to touch your nose and skin.
Staphyloccocus aureus may not cause disease if present as commensal human microflora of human skin and nose but when they get into our body it can cause staph infection if our immune system is weak. Therefore the correct answer is nose and skin.
