Critical Reasoning (CR) | Re: Advertisement: Do you want to be more energetic, vigorous, and physica

Advertisement: Do you want to be more energetic, vigorous, and physically fit? Take a daily supplement of Vita-plus, a vitamin combination containing additional proprietary ingredients. Our studies using hundreds of volunteers show that after just one week of taking 2 capsules daily, participants report being more energetic and alert on average than the average level reported by the National Institutes of Health survey of all Americans.

Which of the following would most strengthen the advertisement’s