In which of the following conditions Parakeratosis most frequently occurs –

Normally, nuclei disappear in stratum corneum. Retention of nuclei within the cells of stratum corneum is referred to as parakeratosis. Parakeratosis is seen in - Normally        →  Mucous membrane of mouth and vagina. Disorders       → Actinic keratosis, Psoriasis, Squamous cell carcinoma, Seborrheic dermatitis, Eczema. Don't get confused with option b; It is seborrheic keratosis, not seborrheic dermatitis. Seborrheic keratosis (also known as senile wart) is a noncancerous benign growth that originates in keratinocytes, seen in old people.