This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Infertility, Subject name: Gynaecology & Obstetrics
Couple with primary infetility, female cause of infeility is ruled out. Semen analysis shows volume of 0.8 ml, azoospermia, fructose is absent what is the net line of management? 
Select and explain. 
A. Testicular FNAC, B. Ultrasound for obstruction, C. Local palpation of vas, D. Karyotyping
B: Ultrasound for obstruction
Answer: B: Ultrasound for obstruction 
Explanation: This is probably a case of obstructive azoospermia. In this condition we need to know the site and nature of blockage. Among the given options ultrasound is the best. Vasogram can also be done. Shaw's Textbook of Gynaecology 16th edition page no 247.