Which of the following is an example of the parenteral route?

The parenteral route refers to the administration of medication by bypassing the gastrointestinal tract, which provides a quicker absorption into the bloodstream. Intravenous injection represents this method perfectly, as it delivers medication directly into the vascular system, ensuring rapid availability and precise dosage. This route is crucial in emergency and critical care settings where time-sensitive treatments are often necessary.

In contrast, the other options involve different administration methods that do not fit the definition of parenteral. Oral administration involves absorbing medication through the digestive system, inhalation therapy typically targets the respiratory system, and transdermal patches deliver medication through the skin. Each of these alternatives processes the medication differently, making intravenous injection the clear example of the parenteral route.