A Firm Wants to Make the Claim That Its Dishwashing

Multiple Choice

A firm wants to make the claim that its dishwashing detergent cuts grease faster than any other dishwashing detergents on the market. Which would be the most objective source of information to prove this claim?

A) a video about the cleaning properties of various detergents produced by one of the firm's competitors
B) the opinion of a popular actor who appears in the firm's commercials
C) an experiment comparing the detergents' cleaning properties conducted by a university with no ties to the firm
D) a research study about the detergent conducted by scientists who work for the firm
E) testimonials from customers who were provided free samples of the firm's detergent