Read the claim and reason.

claim: our school cafeteria should offer more meatless main dishes.

reason: there are a significant number of vegetarians attending our school.

what evidence best supports the student’s reason?

the results of a student survey suggest that twenty-three percent of the students consider themselves vegetarians.
though school food is funded by state and county governments, the menu is determined by school cafeteria staff.
salads and meatless pasta dishes add variety to school menus and provide vegetarians with possible choices.
vegetarians rely on beans, nuts, and greek yogurt as alternate sources of protein in their diets.

The evidence that best supports the student's reason is A. The results of a student survey suggest that twenty-three percent of the students consider themselves vegetarians.

Explanation:

When writing an argumentative text, it is important to provide documentation,  facts or information that indicate whether a statement or proposition is valid or true so as to support the argument of the text. This is called evidence.

Within these options, sentence A is the one that best supports the student's reason because it provides solid and objective data about the students diet, rather than mere opinion or any other piece of information that is not relevant to the claim or its reason.