You can tell that a claim about nutrition is unreliable if: a. it is being made by an advertiser who is paid to make claims b. the evidence used to support the claim comes from a university laboratory c. it is written in a blog on the internet d. it appears in a peer-reviewed scientific journal e. it is being made by a public health nutritionist

a. it is being made by an advertiser who is paid to make claims.

Explanation:

A claim is a statement which is made on the basis of some evidences that are obtain from direct observation or from experimental trials. The claim can be false or unreliable if it is not supported by the evidences obtain from the experimental trails.

A. is the correct option as the advertiser can be paid to publish the false claims for the nutrition so as to promote it's distribution, sales and consumption.