Final answer:
The most likely side effect for a medication taken PO is gastrointestinal because it passes through the digestive system. The oral route is appropriate and convenient for home administration of an antimicrobial for a systemic infection.
Step-by-step explanation:
If a medication is taken PO (by mouth) and you don't know what the drug does, the side effect to pick is most likely A) Gastrointestinal. This is because the medication, once taken orally, will pass through the digestive system, where it could potentially cause gastrointestinal side effects such as nausea, vomiting, diarrhea, or constipation. Regarding the question about the appropriate and convenient route for home administration of an antimicrobial to treat a systemic infection, the answer would be A. oral. This is because oral administration is non-invasive, convenient, and relatively simple for the patient to manage at home. Intravenous administration requires technical skill and equipment, topical application is only suitable for localized infections, and parenteral routes other than IV generally require injection, which can be complex and less convenient for home use.