The correct answer is (d), fluorescent powder.
Fluorescent powder is a type of powder that emits light when exposed to ultraviolet light. This makes it ideal for developing fingerprints on multi-colored surfaces, as the powder will only adhere to the areas where there is fingerprint residue. This makes it easy to see the fingerprints against the background of the surface.
Gold dust, manganese dioxide, and charcoal are all types of powder that can be used to develop fingerprints, but they are not as effective as fluorescent powder on multi-colored surfaces. Gold dust is a very fine powder that can be difficult to see against a dark background. Manganese dioxide is a black powder that can be difficult to see against a light background. Charcoal is a gray powder that can be difficult to see against a dark or light background.
Fluorescent powder is the most effective type of powder for developing fingerprints on multi-colored surfaces because it emits light when exposed to ultraviolet light. This makes it easy to see the fingerprints against the background of the surface.