If the bacterium staphylococcus aureus experiences a cost for maintaining one or more antibiotic-resistance genes, then what should happen in environments from which antibiotics are missing

The bacteria must be outcompeted and substituted by bacteria that have gone this genetic factor. In addition, antibiotic resistance is a natural phenomenon.  Once an antibiotic is used, bacteria that can fight that antibiotic have a greater chance of existence than those that are vulnerable. The vulnerable bacteria are exterminated or inhibited by an antibiotic, subsequent to a selective weight for the existence of resilient tensions of bacteria. Around opposition happens without human deed as bacteria can yield and use antibiotics in contradiction of other microorganisms, prominent to a low-level of the natural assortment of opposition to antibiotics. Though, the presently advanced points of antibiotic resilient bacteria are credited to the abuse and abuse of antibiotics. 

The answer would be c