OG5 阅读 Q22

Choice A is the best answer. In line 14("incredibly...basis."), the passage states that industrial agriculture has become "incredibly efficient on a simple land to food basis." In this context, "simple" suggests something basic or straightforward. 
Choices B, C, and D are incorrect because in the context of a land to food dynamic, the word "simple" suggests something basic or straightforward, not something humble (choice B), something without any decoration or ornamentation (choice C), or something that requires little effort (choice D).