SAT English Practice Question

The passage describes a community of small, interconnected villages in the Andes. The inhabitants of these villages have developed many ingenious methods of coping with their difficult environment. The author states that "these villages are not merely clustered together but are bound together by an intricate web of mutual dependence." Which of the following best describes the author's main point in this passage?

1. A.isolated from each other and have little contact.
2. B.part of a large and complex network of interdependence.
3. C.located in a challenging environment.
4. D.struggling to survive due to a lack of resources.