题目选项分析

Sammy: For my arthritis, I am going to try my aunts diet: large amounts of wheat germ and garlic. She was able to move more easily right after she started that diet

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

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

【选项】Arthritis is a chronic condition whose symptoms improve and worsen from time to time without regard to diet.