Which type of advertisement emphasizes scientific data and facts to support a product's claims?

The correct choice is B, as scientific evidence is the type of advertisement that relies on empirical data, research findings, and factual information to substantiate the claims made about a product. Advertisements using scientific evidence aim to persuade consumers by presenting verifiable studies or statistics that illustrate the effectiveness or benefits of the product. This approach instills trust and credibility, as it appeals to consumers' rationality and desire for products that are supported by scientific expertise.

In contrast, testimonials involve personal stories or endorsements from individuals who have used the product, which rely on subjective experiences rather than objective data. The bandwagon approach encourages consumers to join the crowd and purchase a product because others are doing so, often without factual support. Lastly, plain folks advertising attempts to connect with consumers by portraying the product as one that everyday people use, focusing on relatability rather than scientific claims.