This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Lichen planus and Other papulosquamous disorders, Subject name: Dental
[{'content': 'A 16 year-old boy presented with asymptomatic, multiple, erythematous, annular lesions with a collarette of scales at the periphery of the lesions present on the trunk. The most likely diagnosis is: \nSelect and explain. \nA. Lichen planus, B. Seborrhic dermatitis, C. Pityriasis rosea, D. Tinea versicolor', 'role': 'user'}, {'content': 'Answer: C \nExplanation: Multiple, erythematous, annular lesions with a collarette of scales at the periphery of the lesions present on the trunk is suggestive of Pityriasis rosea. Lichen planus Purple Polygonal Pruritic Papules; Lacy white markings, Associated with mucous membrane lesions. Seborrheic dermatitis Central facial erythema with overlying greasy, yellowish scale. Pityriasis rosea - Rash preceded by herald patch; - Oval to round plaques with trailing scale; - Affects trunk and eruption lines up in skin folds giving a "fir tree"-like appearance; Tinea versicolor (Malassezia furfur) - Hyperpigmented or hypopigmented scaly patches on the trunk; - Characteristic mixture of hyphae and spores on KOH preparation (\'spaghetti and meatballs\' appearance) -Rx: Topical Selenium sulfide lotion or azoles', 'role': 'assistant'}]