This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Superficial Mycoses, Subject name: Skin
[{'content': 'Black piedra is caused by - \nSelect and explain. \nA. Piedraia hortae, B. Trichosporon asahii, C. Trichosporon ovoides, D. Trichosporon inkin', 'role': 'user'}, {'content': "Answer: A \nExplanation: Ans. is 'a' i.e., Piedraia hortae o Piedra is an asymptomatic superficial fungal infection of the hair shaft also known as trichomycosis nodu- laris. Black piedra is caused by Piedraia hortae, whereas white piedra is caused by pathogenic species of the Trichosporon genus, namely Trichosporon asahii, Trichosporon ovoides, Trichosporon inkin, Trichosporon mucoides, Trichosporon asteroides, and Trichosporon cutaneum.", 'role': 'assistant'}]