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: Skin
[{'content': 'Onychomycosis is most commonly caused by ? \nSelect and explain. \nA. a) Trichophyton rubrum, B. Trichophyton mentagrophytes, C. Epidermatophyton floccosum, D. a) Candida', 'role': 'user'}, {'content': "Answer: A \nExplanation: Ans. is 'a' i.e., Trichophyton rubrum Tinea Unguium (Onychomycosis) Tinea unguium is dermatophytic infection of fingers and toe nails. Most common causative species is T-rubrum. Toe nails are more commonly involved. T. Unguium may be of two types : ? Distal subungal onychomycosis : - This is most common type of fungal infection of nail (90%). It stas at the distal edge of the nail plate and slowly grows inwards to involve entire nail plate. Proximal Subungal onychomycosis : - Stas at the base of nail and slowly involves the entire nail plate.", 'role': 'assistant'}]