the statement that best summarizes samantha's claim is c. fast food restaurants would profit from offering vegan meals.
samantha explains her experience as a vegan going to eat to fast food restaurants and she concludes her argument by saying "by not offering vegan meals, fast food restaurants are missing out on additional sales." in this conclusion, readers can infer that samantha believes fast food restaurants would increase their sales if they offered vegan meals and, thus, profit from it.