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 25 year old infeile male underwent semen analysis. Results show : sperm count - 15 million/ml; pH - 7.5; volume - 2 ml; no agglutination is seen. Morphology shows 60% normal and 60% motile sperms. Most likely diagnosis is: 
Select and explain. 
A. Normospermia, B. Oligospermia, C. Azoospermia, D. Aspermia
B: Oligospermia
Answer: B: Oligospermia 
Explanation: Oligospermia is defined as a sperm count below 20 million/mL. Ref: Textbook of Gynecology By D C Dutta, 4th Edition, Pages 217, 218, 225 ; Current Obs and Gynae Diagnosis and Treatment 9th Edition, Page 982