What does the below diagram explain?
Both A and C
Microorganisms ( bacteria) are able to withstand antimicrobial drugs(e.g. antibiotics).This is because of a unique feature in their DNA that helps them to survive better.
When the resistant strain bacteria replicate (the one with the unique feature/DNA) the resistant trait is passed on to the daughter cells. The resistant trait can also be exchanged when there is gene transfer as seen in the above diagram. The acquired resistant trait helps the daughter cells to survive certain adverse conditions better than the other bacteria.