Which reagent is used in Steiner and Steiner staining procedure?

• A. Hydroquinone
• B. Iodine
• C. Formalin
• D. Sucrose

Answer: (A)

Steiner and Steiner staining relies on a silver impregnation step followed by development of the silver image. The developing step needs a reducing agent to convert silver ions trapped in the tissue into metallic silver, which creates the visible dark deposits that outline the target elements. Hydroquinone performs this reducing/developing function, giving sharp, high-contrast staining.

Other options serve different roles in various steps (fixation with formalin, osmotic or other preparative roles with sucrose, or iodine used in some oxidative/mordant steps), but none act as the developing/reducing agent in this procedure.