This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Medicine
Pseudohermaphroditism in a female child is most commonly due to - 
Select and explain. 
A. 21 α hydroxylase deficiency, B. 17 α hydroxylase deficiency, C. 11 β hydroxylase deficiency, D. 3 β Hydroxysteroid dehydrogenase deficiency
A: 21 α hydroxylase deficiency
Answer: A: 21 α hydroxylase deficiency 
Explanation: Classic 21 α hydroxylase deficiency is the most common cause of Ambiguous genitalia in a new born.

Pseudo hermaphroditism

A congenital abnormality of the external genitalia and of the body in which one possesses sex glands of one sex but genitals of the opposite sex.