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: Microbiology
The diagnosis of gonorrohea is established by: 
Select and explain. 
A. Complement fixation tests, B. Pili agglutination tests, C. Hem agglutination tests, D. All of the above tests
A: Complement fixation tests
Answer: A: Complement fixation tests 
Explanation: Ans. is. a. Complement fixation tests