Which staining method results in fat being stained brilliant red and nuclei blue?

The staining method that results in fat being stained brilliant red and nuclei blue is Oil Red O. This dye is specifically designed for lipophilic substances, allowing it to selectively stain neutral lipids and triglycerides in tissues. When Oil Red O is applied to a sample, it binds to the fats, causing them to appear bright red under a microscope.

In addition to highlighting lipid content, the staining procedure can be combined with a counterstain that renders nuclei blue, enhancing the contrast between the fat deposits and cell nuclei. This dual staining is particularly useful in histopathology for identifying conditions associated with lipid accumulation.

Other methods listed do not achieve this specific color differentiation. For example, Rhodamine B is a fluorescent dye typically used in a different context and does not present the same color outcomes for fats and nuclei. Sudan IV also stains lipids but does not produce the distinctive brilliant red that Oil Red O does when paired with a blue counterstain for nuclei. Lastly, the Feulgen stain is specifically used for DNA and does not target lipids at all, resulting in entirely different staining properties. Thus, Oil Red O is the appropriate choice for the described staining characteristics.