Final answer:
For the home administration of an antimicrobial drug to treat a systemic infection, the oral route is generally preferred due to its convenience and ease of self-administration.
Step-by-step explanation:
The route of administration for a drug is an essential consideration for drug therapy. For antimicrobial treatment of a systemic infection that would be appropriate and convenient for home administration, the oral route (Option A) is generally preferred. This is because oral medications can be taken easily and conveniently at home, which is not the case for intravenous administration that typically requires a healthcare setting. Other routes, such as topical and parenteral (including intramuscular), may be used in different scenarios depending on factors such as the drug's absorption in the GI tract, patient's ability to take oral medications, or the targeted area of treatment.
The drug "2 gatt a.u." is most likely to be administered intramuscularly. This means that the drug is injected into the muscle tissue using a needle and syringe. Intramuscular administration is a common route for certain medications that are not suitable for oral administration and need to be absorbed quickly into the bloodstream.