The best choice that supports the student's conclusion is:
(Choice B) Compared with participants who saw the control review, participants who saw the low-anger review rated the review as slightly more helpful, whereas participants who saw the high-anger review rated the review as less helpful.
This choice clearly illustrates the distinction between the effects of low and high degrees of anger on readers' perceptions of the helpfulness of the review, confirming that the presence of a low degree of anger may not harm perceptions, while a high degree of anger worsens them.