Which statement correctly describes one of the advantages of oral drug administration?

A. Systemic side effects are less common than other routes: Oral medications are absorbed into systemic circulation and can produce widespread effects throughout the body. Because they undergo distribution to multiple tissues, systemic adverse effects remain possible. In addition, first-pass metabolism does not eliminate the risk of systemic toxicity. B. Simple and cheap when compared to other routes: The oral route is noninvasive, does not require sterile equipment, and can be self-administered without specialized training. It avoids costs associated with intravenous supplies, infusion pumps, or skilled personnel. These characteristics make oral administration one of the most economical and convenient methods of drug delivery. C. 100% of the dose is always received by the patient: Oral medications are subject to incomplete absorption in the gastrointestinal tract and first-pass metabolism in the liver. Factors such as gastric pH, motility, food interactions, and hepatic enzyme activity can reduce bioavailability. As a result, systemic availability is often significantly less than 100%. D. Drug action occurs rapidly with this route: Oral medications must dissolve, be absorbed through the gastrointestinal mucosa, and pass through hepatic circulation before reaching systemic distribution. This process delays onset compared to intravenous or inhaled routes. Rapid therapeutic effects are generally not characteristic of oral administration.