OG详解-OG3 文法 Q12

Choice B is the best answer. The sentence effectively emphasizes Kind’s methodology: examining the student policies of 132 medical schools for guidelines about student social media use. 
Choice A is incorrect. The sentence specifies how many medical schools’ student policies are available online; it doesn’t emphasize the study’s methodology. Choice C is incorrect. The sentence emphasizes the study’s results, not the study’s methodology. Choice D is incorrect. The sentence emphasizes the aim of the study, not the study’s methodology