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
"Giardiasis" is best diagnosed by: 
Select and explain. 
A. CFT, B. Cyst and trophozite in stool, C. Haemaglutination, D. None
B: Cyst and trophozite in stool
Answer: B: Cyst and trophozite in stool 
Explanation: Cyst and trophozite in stool