Final answer:
Parenteral routes such as intravenous or intramuscular injections offer direct entry into the bloodstream, ensuring high plasma levels of medication and quick effect. This method is typically used when oral administration is not suitable or when the drug is poorly absorbed through the GI tract.
Step-by-step explanation:
Parenteral routes offer direct entry into the bloodstream, which is choice (C) among the options provided. This method bypasses the gastrointestinal (GI) tract, delivering medication such as antimicrobials effectively and quickly, and is especially beneficial for patients that cannot take oral medications. Parenteral administration typically includes intravenous and intramuscular injections and is often performed in healthcare settings, ensuring that plasma levels of the drug are substantially higher than those achieved by oral routes.
For home administration of an antimicrobial to treat a systemic infection, the most appropriate and convenient route would generally be oral (A), provided that the drug is well-absorbed in the GI tract. Nonetheless, if the drug is not absorbed well orally, or the patient is unable to take medication by mouth, parenteral routes might be considered, even for home use, if proper medical support and monitoring are available.