Answer:
The correct answer is: D) a drug that blocks gene expression in circular chromosomes.
Step-by-step explanation:
Antibiotics are the drugs that are mostly used when it comes to treating bacterial infections because of their effective mechanisms in killing bacteria and/or preventing their spread.
Bacteria have the ability to colonize and infect different organisms by making use of highly diverse mechanisms, some of which involve the use of toxins or the inhibition of the host's immune system.
Bacteria are prokaryotic individuals - instead of having a nucleus containing DNA in multiple chromosomes like eukaryotes have, they have one single circular chromosome that holds all or most of all their genetic information. If we wanted to treat a plant (which is a eukaryotic being) for a bacterial infection, we should aim to block the expression of genes in circular chromosomes, which is a distinct feature in bacteria.
If we were to give the plant a drug that interferes with mitochondria function or destroys the central vacuole, we would only be affecting plant cells and probably killing the plant. A drug that disrupts cell walls would affect the bacteria but would kill the plant as well (both organisms have cell walls). The only viable option out of the mentioned is using a drug that inhibits gene expression in circular chromosomes.