When categorizing medications, drug classifications may be defined by the effects of the drug and:

Choice A reason: Classifications like “analgesics” pair effects (pain relief) with symptoms (pain); this pharmacological basis groups drugs by therapeutic purpose and mechanism. Choice B reason: Dosage varies within classes; it’s not a defining trait, as classifications focus on action (e.g., beta-blockers), not specific amounts administered. Choice C reason: Tolerance is patient-specific, not a classification criterion; drugs are grouped by effect and symptom relief, not individual response variations. Choice D reason: Nursing implications guide administration, not classification; categories stem from pharmacology (e.g., antihypertensives), not care protocols or implications.