This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Endometriosis and dysmenorrhea, Subject name: Gynaecology & Obstetrics
Best investigation endometriosis is : 
Select and explain. 
A. Laparoscopy, B. USG, C. X-ray pelvis, D. CT Scan
A: Laparoscopy
Answer: A: Laparoscopy 
Explanation: Laparoscopy is the gold standard in the diagnosis of endometriosis. The diagnosis should be validated by peritoneal and tissue biopsy, because corpus luteal haematoma can resemble a chocolate cyst. Reference: Shaw's Textbook of Gynaecology 16th edition page no 415