Which of the following is an FDA-approved indication for fentanyl?

A. Fentanyl is a potent mu-opioid receptor agonist indicated for the management of chronic, severe pain. The transdermal system provides continuous systemic delivery of the drug over 72 hours. It is reserved for opioid-tolerant patients requiring around-the-clock long-term opioid treatment. B. This agent does not possess sympathomimetic activity or alpha-adrenergic agonist properties required to reduce nasal mucosal swelling. It lacks the pharmacological profile of a decongestant like pseudoephedrine. It is not indicated or used for the management of congestion. C. Fentanyl has no therapeutic effect on the inflammatory or histaminergic pathways associated with allergic rhinitis. It does not act as an H1-receptor antagonist or a nasal corticosteroid. It is not a clinical intervention for seasonal or perennial allergies. D. Opioid analgesics do not inhibit the hypothalamic thermoregulatory center through the suppression of prostaglandin E2 synthesis. Fentanyl lacks the antipyretic properties found in cyclooxygenase inhibitors like acetaminophen or ibuprofen. It is never indicated for the management of fever.