Which of the following is not a parenteral route of administration?

The choice indicating the oral route is not a parenteral method of administration because parenteral routes refer specifically to methods that bypass the gastrointestinal tract. Parenteral administration involves delivering medication directly into the body through injections, which include intravenous, intramuscular, and subcutaneous routes. These routes allow for rapid absorption and immediate effect, which is essential for certain medical conditions or treatments where oral administration may be ineffective or delayed. In contrast, the oral route involves passing medications through the digestive system, where they are absorbed in the gastrointestinal tract. This significant difference in the mechanism of action clearly identifies the oral route as the one that does not fall within the definition of parenteral administration.