Washing powders contain detergents in the range of (by mass): 

We must be aware that washing powder is a type of detergent used to clean clothes. We have the capacity to produce liquid and powdered detergent. Builders, surfactants, soil anti-deposition agents, corrosion inhibitors, enzymes, perfumes, fillers, colours, and foam regulators are a few examples of the components.

A surfactant combination (or surfactants) that possesses cleaning characteristics in diluted solutions is referred to as a detergent. Alkylbenzene sulfonates are used to create these compounds. Alkylbenzene sulfonates are a member of a class of substances related to soap.

Because detergents' polar sulfonate is less likely than soap's polar carboxylate to adhere to the calcium and other ions present in hard water, detergents are more soluble in it.

Synthetic detergent salts with cleansing characteristics in water can be classified as salts of sodium or potassium with a long chain containing alkyl benzene sulphonic acid or salts of sodium or potassium with a long chain containing alkyl hydrogen sulphate.

In a washing powder, the composition of builders is 50%, surfactants are 7%, anti-solid positives are 2% and the remaining is detergents. Thus washing soda contains 15-30% detergents.

Hence, the correct answer is option D.