Sammy: For my arthritis, I am going to try my aunt's diet: large amoun

Understanding the argument - ­
Sammy: For my arthritis, I am going to try my aunt's diet: large amounts of wheat germ and garlic. She was able to move more easily right after she started that diet. - Notice "right after." Is it establishing any causal connection that "wheat germ and garlic" caused her to move to move easily? No. It's just saying "right after" she started it. Just like, right after dinner, I went for a walk. It's just a correlation. 

Pat: When my brother began that diet, his arthritis got worse. But he has been doing much better since he stopped eating vegetables in the nightshade family, such as tomatoes and peppers. - look at "when." Is it saying that "wheat germ and garlic" caused his brother's condition to worsen? No. Just correlation. Then it introduces a contrast by "but," saying that when he stopped eating Vegetables in the nightshade family, he felt better. Did the argument say that eating vegetables in the nightshade family caused him to have a better condition? No. It's just a correlation. 

Which of the following, if true, would provide a basis for explaining the fact that Sammy's aunt and Pat's brother had contrasting experiences with the same diet?

Scope of the argument - We need to why both had a different experience with the same diet. Which diet? Wheat germ and garlic. Is our scope anyway connected to "eating Vegetables in the nightshade family," No. So, anything talking about "eating Vegetables in the nightshade family" will be out of scope. 

Option Eliminaiton. - 

A. A change in diet, regardless of the nature of the change, frequently brings temporary relief from arthritis symptoms. - worsens the paradox. 

B. The compounds in garlic that can lessen the symptoms of arthritis are also present in tomatoes and peppers. - Worsens the paradox. Becasue if there are compounds that can lessen the symptoms, so he should have felt better? Isnt it? But he is not. So opposite. 

C. Arthritis is a chronic condition whose symptoms improve and worsen from time to time without regard to diet. - oh, ok. So it's just a coincidence. This is okay because the argument doesn't talk about any causal connection anyway.

D. In general, men are more likely to have their arthritis symptoms alleviated by avoiding vegetables in the nightshade family than are women. - "Vegetables in the nightshade family" are out of scope. 

E. People who are closely related are more likely to experience the same result from adopting a particular diet than are people who are unrelated. - We don't know anything about their relationship. Out of scope.