This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Systemic histology, Subject name: Anatomy
Anal transition zone is ? 
Select and explain. 
A. columnar - cuboidal - squamous, B. columnar-squamous - cuboidal, C. squamous-cuboidal-columnar, D. cuboidal-squamous-columnar
A: columnar - cuboidal - squamous
Answer: A: columnar - cuboidal - squamous 
Explanation: Anal transition zone is Columnar-Cuboidal-Squamous Dentate line (Pectinate line)is Sqaumocolumnar junction below to it is Squamous epithelium and above to it is transitional zone which is Columnar - Cuboidal epithelium.