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: Physiology
Axillary hair growth is caused by? 
Select and explain. 
A. Testosterone, B. Estrogen, C. Prolactin, D. Estrogen in women and androgens in man
A: Testosterone
Answer: A: Testosterone 
Explanation: Testosterone REF: Ganong's 22nd ed p. 430 Secondary sexual hair production in both man and woman is under control of androgens