The layer of the epidermis that contains the cells undergoing mitosis is the stratum

A. corneum: The stratum corneum is the outermost layer of the epidermis composed of fully keratinized, dead cells. These cells provide protection but are incapable of undergoing mitosis.

B. lucidum: The stratum lucidum is a clear layer found only in thick skin, such as the palms and soles. It consists of dead keratinocytes that have lost their nuclei, so mitosis does not occur here.

C. granulosum: The stratum granulosum contains keratinocytes that are beginning to die and fill with keratohyalin granules. Mitosis does not take place in this layer, as cells are transitioning to terminal differentiation.

D. basale: The stratum basale is the deepest layer of the epidermis where keratinocyte stem cells actively divide. Continuous mitosis in this layer replenishes the epidermis and pushes new cells toward the surface.

E. spinosum: The stratum spinosum provides strength and flexibility with its desmosomal attachments. While cells here may appear metabolically active, true mitotic activity primarily occurs in the stratum basale below it.