The correct answer is D) A study published by the Mayo Clinic called, "Antioxidants: Do They Help Prevent Cancer?"
Step-by-step explanation:
Information is biased when it supports a specific interest or perspective which means it is not objective. This occurs if the authors of the article, book or source benefit from the information. For example, a study sponsored by a company to prove the company products' work is likely to contain biased information.
According to this, the source that is likely to contain bias-free information is D because this study was published by the Mayo Clinic that is a not-for-profit organization and therefore it is likely the information is objective as the author has no interest in defending a certain position or point of view about cancer. Also, this study is likely to have only scientific purposes.