This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: miscellaneous, Subject name: Dental
[{'content': 'Depigmenting agent of choice in in treatment of dermatological disorders is - \nSelect and explain. \nA. Hydroquinone, B. Zinc, C. Kojic acid, D. Azelaic acid', 'role': 'user'}, {'content': 'Answer: A \nExplanation: <p>DEPIGMENTING AGENTS:- Include agents like hydroquinone(2%-5%),azelaic acid (10%-20%), glycolic acid (6%-12%) and monobenzene. They act by inhibiting tyrosinase enzyme. Hydroquinone is most commonly used.It can be combined with steroids and retinoids in the treatment of melasma. Kligmans regimen- 5% hydroquinone+0.1% tretinoin +0.1% hydrophilic ointment. Newer agents-Arbutin and kojic acid.They lighten hyperpigmented patches. Used in melasma, freckles. {Reference: IADVL textbook of dermatology, vishalakshi Vishwanath pg no.379}</p>', 'role': 'assistant'}]