Nutritionist: The healthiest soups all contain spinach and various other vegetables. Few vegetable soups are thought to be rich in nutrients. The lower the nutritional benefit of a food, the less healthy it is. No vegetable soup that does not contain spinach then should be considered healthy. Which one of the following would it be most relevant to investigate in evaluating the conclusion of the nutritionist's argument? ['Is spinach the only high-nutrient vegetable that is used in soup?', 'Which vegetables contain the least nutrients?', 'Do substances added during the canning process make soup healthier?', 'Are cream soups healthier than vegetable soups?']