The main purpose of the passage is to

Choice B is the best answer. The passage focuses mainly on presenting the critique of the Internet offered by Sherry Turkle, who “has become increasingly wary of the capacity of online spaces to fulfill us in the ways we seem to want them to” and feels that the Internet encourages “a seductive but dangerous habit of mind.” Choice A is incorrect because only Sherry Turkle’s assessment is presented in the passage. Choice C is incorrect because the passage does not propose a remedy; it only presents Turkle’s assessment of a problem. Choice D is incorrect because while the passage does present some details that might be considered background (e.g., that Turkle works at the Massachusetts Institute of Technology), the passage focuses mainly on Turkle’s critique of the Internet’s ability to support self-invention.