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: Unknown
Dermatophytes involve - 
Select and explain. 
A. Stratum corneum, B. Stratum lucidum, C. Stratum malpighi, D. Stratum basal
A: Stratum corneum
Answer: A: Stratum corneum 
Explanation: Ans. is 'a' i.e.. Stratum comeum o Dermatophytes are keratinophilic fungi, living only on the superficial dead keratin. That is why they infect skin, hair and nail. In skin they infect most superficial layer of the epidermis i.e. stratum corneum. They do not penetrate living tissues. Dermatophytes cause a variety of clinical conditions, collectively known as dermatophytosis, tinea or ringworm. Dermatophytes have been classified into 3 genera:- trichophyton, microsporum, epidermophyton:Trichophyton affects;- skin, hair, nails.Microsporum affects - skin, hair (nails are not affected)Epidermophyton affects:- skin, nails (hair are not affected)o Deep fungal infections (eg:- mycetoma, chromoblastomycosis, pheohyphomycosis, sporotrichosis, lobomycosis, rhinosporidiosis) involve subcutaneous tissue.o Dermatophytosis is itchy and scaly.