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: Gynaecology & Obstetrics
A 20 year 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: Ans. is c i.e. Testosterone "Specifically women with an abrupt onset, typically within several months or sudden worsening of virilising signs should prompt concern for a hormone producing ovjarian or adrenal tumor. Serum testosterone levels may be used to exclude these tumours." Rapidly developing hirsutism with amenorrhoea and change in voice is suggestive of masculinizing tumour like Arrhenoblastoma or androblastoma which are invariably associated with raised testosterone (T > 200 ng / dl).