This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Pharmacology
Adapalene is used in treatment of: 
Select and explain. 
A. Acne vulgaris, B. Atopic dermatitis, C. Psoriasis, D. All of the above
A: Acne vulgaris
Answer: A: Acne vulgaris 
Explanation: Adapalene (Differin) is a derivative of naphthoic acid that resembles retinoic acid in structure and effects. It is applied as a 0.1% gel once daily. Unlike tretinoin, adapalene is photochemically stable and shows little decrease in efficacy when used in combination with benzoyl peroxide. Adapalene is less irritating than tretinoin and is most effective in patients with mild to moderate acnevulgaris Ref: Katzung 11th edition Chapter 61.