Which of the following is a common route of drug administration?

Oral administration is a common route of drug administration due to its ease of use and patient compliance. This method involves swallowing a pill, tablet, or liquid form of medication which is then absorbed through the gastrointestinal tract. It's widely utilized because many patients are familiar with taking medications orally, making it a practical choice for chronic conditions or long-term therapies.

Other routes, such as inhalation, transdermal, and intranasal, are also used but are often more specialized for certain conditions or types of drugs. Inhalation is especially beneficial for respiratory conditions, while transdermal administration is used for sustained delivery of medications through the skin. Intranasal delivery provides a quick onset of action for certain medications but may not be as broadly applicable or preferred as oral administration for general medication needs. Therefore, the oral route remains the most common and widely accepted for delivering a variety of pharmaceutical therapies.