Concept:Borax solution is mildly alkaline and helps to break down the acidic compounds found in coffee stains.
Explanation:Coffee stains contain acidic substances that cling to fabric fibres.
Borax, or sodium tetraborate (
Na2B4O7⋅10H2O), dissolves in water to form a mildly alkaline solution.
This alkaline solution neutralises the acidic stain and makes it easier to wash away.
Kerosine and turpentine are organic solvents better suited to oily stains, while ammonia solution is alkaline but is not the most effective or commonly recommended agent for coffee stains.
Therefore, a solution of borax in water is the best choice for removing coffee stains.
Answer:C. A solution of borax in water.