This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: General, Subject name: Skin
[{'content': 'Parakeratosis is: \nSelect and explain. \nA. Absence of nucleus in stratum corneum, B. Persistence of nucleus in stratum corneum, C. Thickening of corneum layer, D. Thickening of prickle cell layer', 'role': 'user'}, {'content': 'Answer: B \nExplanation: Ans. B. Persistence of nucleus in stratum corneum* Stratum corneum is the most superficial layer of the skin and is devoid of nucleus.* Parakeratosis is retention of nucleus in stratum corneum* If there is presence of nucleus in this layer it can be a normal case or can be associated with some pathology.* Normally nucleus in corneum persists in vagina and in mucous membrane of mouth.* Pathologies having nucleus in stratum corneum: seborrheic dermatitis, squamous cell CA, Actinic keratosis, psoriasis, etc.', 'role': 'assistant'}]