In a magazine advertisement, as they claim about the product having ceramic pellets, changing the PH of the water, about reducing wear on their clothes, contaminants in the environment.
So, the important thing they should do in the advertisement to give consumer more confidence is to prove their claims with extensive product testing and also they should reveal their results with the customers.
Answer: The answer would be information about product testing in a study that includes a control group.
Explanation: