This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Polycystic Ovarian Syndrome, Subject name: Gynaecology & Obstetrics
A 20 yrs old young girl, presents with history of rapidly developing hirsutism and Amenorrhea with change in voice. To establish a diagnosis you would like to proceed with which of the following tests in blood: 
Select and explain. 
A. 17-OH progesterone, B. DHEA, C. Testosterone, D. LH +FSH estimation
C: Testosterone
Answer: C: Testosterone 
Explanation: Rapidly' progressing hirsutism points to developing androgen secreting tumors, which could be a Leydig seoli tumor of the ovary. For which estimation of androgens specifically serum testosterone should be an initial investigation along with a pelvic scan A 17 OH progesterone should be estimated as well to rule out a late onset Congenital adrenal hyperplasia.