Answer:
C. Resistance
Step-by-step explanation:
Medicines are substances that act in the failure of pathogens to humans, or also resulting in inhibition of their development, acting selectively in the population of microorganisms, such as bacteria. However, some species may manifest drug resistance, usually occurring through mutations that provide the synthesis of enzymes capable of conferring inactivation of such substances.
When this resistance is established, the drug cannot prevent the pathogen from completing its development within a host body. That is, resistance is the term used to describe the ability of a pathogen to adapt to a particular drug so that the drug is no longer effective.