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
Staining technique for cryptosporodium: September 2012 
Select and explain. 
A. Indian ink, B. Modified acid fast, C. Giemsa, D. Methylene blue
B: Modified acid fast
Answer: B: Modified acid fast 
Explanation: Ans. B i.e. Modified acid fast Staining of cryptosporidium Traditional parasitology stains (e.g., Giemsa) are of limited value. They do not differentiate between oocysts and similarly-sized fecal yeasts (the main differential diagnosis of Cryptosporidium in microscopy) and other debris. Modified acid-fast staining technique is a simple and effective method: the oocysts stain bright red against a background of blue-green fecal debris and yeasts. The acid-fast staining technique has been modified and improved, including: hot and cold modified acid-fast stains; incorporation of dimethyl sulfoxide (DMSO); and incorporation of the detergent tergitol.