This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Anatomy of skin, Subject name: Dental
Keratin 5 and 14 are produced in which layer 
Select and explain. 
A. stratum corneum, B. stratum granulosum, C. stratum spinosum, D. stratum basale
D: stratum basale
Answer: D: stratum basale 
Explanation: Stratum Basale It has mitotically active cuboidal cells from which the upper layers of the epidermis are derived. Attached to dermis by hemidesmosomes. Keratins 5 and 14 produced here. Cellular proliferation stimulated by various factors, including trauma and UV (|ornithine decarboxylase expression is associated with (a/w) proliferative states). Ornithine decarboxylase is inhibited by coicosteroids, retinoids, and vitamin D3. 10% of cells in the basal layer are stem cells, which give rise to other stem cells and transient amplifying cells that can still replicate, but only for a few cycles, until they reach a terminal differentiation phase, where they move upwards and eventually desquamate. Ref:- Review of Dermatology by Alikhan; pg num:- 1,2