Final answer:
In adults, up to 3 cc of a drug can be administered per injection site by IM injection. For home administration of an antimicrobial to treat a systemic infection, the oral route is appropriate and convenient.
Step-by-step explanation:
The amount of a drug that you can administer per site by IM (intramuscular) injection in adults typically varies depending on multiple factors, including the medication's volume, viscosity, and the muscle's size. However, in general, you can safely administer up to 3 cc of a drug per injection site in adults. Administering more than this amount may increase the risk of discomfort, leakage, and inadequate absorption. Regarding the question about the appropriate route for home administration of an antimicrobial to treat a systemic infection, the oral route (A. oral) is commonly used.
It is convenient for patients because it does not require sterile technique or special equipment and can be done by the patients themselves or with minimal assistance.