Which sequence of colors indicates increasing concentrations of reducing sugar in a semi-quantitative Benedict's test?

In a semi-quantitative Benedict's test, the sequence of colors produced in relation to the concentration of reducing sugars demonstrates a clear pattern of increasing concentration. The reaction involves the reduction of copper(II) ions to copper(I) oxide, which precipitates out of solution and varies in color depending on the amount of reducing sugar present.

The correct sequence, starting from the lowest concentration to the highest, is green to yellow to orange and finally red. In this context, green typically indicates a very low presence of reducing sugars, while as the concentration increases, the colors transition through yellow and orange, culminating in a bright red when there is a high concentration of reducing sugars.

This color progression is attributed to the varying levels of copper(I) oxide that form during the reaction—lower levels yield green colors while higher levels result in deeper red colors. Hence, the choice that accurately reflects this increasing concentration of reducing sugar through the corresponding color changes is indeed green, yellow, orange, and red.