This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: parasitology, Subject name: Microbiology
In formal ether concentration technique, which layer contain parasites - 
Select and explain. 
A. Ether, B. Fecal debris, C. Formal water, D. Sediment
D: Sediment
Answer: D: Sediment 
Explanation: None