Which of the following is an example of qualitative observation? select one of the options below as your . a. joseph is observing the color difference in the reaction mixture of each of the test samples to see what types of proteins are present in them.. b. joseph is measuring the color of the reaction mixture colorimetrically to see the concentration of proteins in the sample.. c. joseph is observing the color of the reaction mixture to see whether proteins are present in the given solution..