Which of the following abbreviations represents administration of medication "by mouth"?

The abbreviation that represents administration of medication "by mouth" is "po," which stands for the Latin term "per os." This term directly translates to "by mouth," indicating that the medication should be taken orally. In the practice of pharmacy, it's crucial to accurately understand and use abbreviations, as they communicate essential instructions regarding how a medication should be administered.

Other terms listed, such as "prn," refer to medications that are to be taken "as needed," while "pm" commonly indicates "post meridiem," referring to the time of day (afternoon or evening). "Pc" stands for "post cibum," meaning "after meals." Each of these abbreviations serves different purposes and contexts in medication administration, but the specific instruction for oral intake clearly corresponds to the abbreviation "po."