A drug in buccal dosage form would be placed:

Placing a drug in the rectum refers to the rectal route of administration, not buccal. Rectal administration is utilized for medications that may be irritating to the stomach or when oral administration is not feasible due to vomiting or unconsciousness.

Placing a drug in the ear is associated with otic administration for treating ear-related conditions like infections or inflammation. Otic medications are not intended for absorption through the cheek mucosa like buccal formulations.

Placing a drug under the tongue refers to sublingual administration, a route where medications are absorbed through the rich network of blood vessels beneath the tongue. Although similar to buccal administration in bypassing the digestive system, sublingual placement is distinct from buccal delivery in terms of specific absorption sites.