This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: All India exam, Subject name: Pharmacology
In formol-ether concentration technique, which layer contains the parasites? 
Select and explain. 
A. Ether, B. Fecal debris, C. Formal water, D. Sediment
D: Sediment
Answer: D: Sediment 
Explanation: Concentration techniques include:Sedimentation techniquesFormol-ether concentration techniqueFormol detergent concentration techniqueFloatation techniquesSodium chloride floatation techniquesZinc sulphate floatation techniqueSugar floatation techniqueFormol-ether concentration technique is overall best sedimentation technique. It is rapid and gives good results. The figure shown in reference mentioned clearly shows sediment-containing parasites.