Question Explanation:
Conclusion: Anyone aware of this fact will surely choose vegetarianism over any other diet.
Premises: A growing number of people who are seeking a healthier way to live are turning to vegetarianism. The average person who switches to a vegetarian diet will lose fifteen pounds in a year.
Assumption: Anyone seeking a healthier way to live wishes to lose weight.
The question stem asks to challenge the conclusion, so this is a weaken question. The passage states that the average person who switches to a vegetarian diet will lose fifteen pounds in a year. Based on this weight loss, the passage concludes that anyone aware of this fact will surely choose vegetarianism over any other diet. In order to support the claim that anyone aware of the weight-losing effects of vegetarianism will surely choose such a diet, the passage must assume that all people seeking a healthier way to live wish to lose weight. As this is a weaken question, the correct answer will attack this assumption. Evaluate the answer choices.
Choice A: No. How expensive the diet may be is out of scope. The correct answer must weaken the assumption that anyone seeking a healthier way to live wishes to lose weight. The cost of vegetarianism or any other diet is not relevant.
Choice B: No. Weight loss due to exercise is out of scope. The argument is concerned with the weight loss effects of a vegetarian diet, not that of any of the other ways to lose weight.
Choice C: Correct. According to this answer choice, a person seeking a healthier way to live could be aware of the weight-losing effects of vegetarianism, yet choose not to adopt such a diet because that person is not concerned...with weight loss.
Choice D: No. Sufficient amount of weight is out of scope. The argument relies on the universal desire to lose weight, not whether a certain amount of weight loss is sufficient for everyone.
Choice E: No. This choice is out of scope. The passage is concerned with the weight-losing effects of a vegetarian diet, not small amounts of fish or whatever else a person may choose to eat.
The correct answer is choice C.