Explanation
Correct answer: D.
Choice D is the best answer. According to the author of Text 1, Moore’s definition of common sense—things we instinctively know are true—includes the belief that we all “exist in a world with other objects.” The author of Text 1 describes this notion as both “obvious” and “groundbreaking.” So it’s safe to infer that the author would observe that Moore would respond to external world skeptics by arguing that since everyone instinctively knows that things exist outside of their own minds, then external world skepticism must be wrong.
Why the other choices are wrong
Choice A
Choice A is incorrect. We can’t infer that the author of Text 1 would respond this way to external world skeptics. If anything, the author of Text 1 seems to agree with Moore.
Choice B
Choice B is incorrect. We can’t infer that the author of Text 1 would respond this way to external world skeptics. The author of Text 1 never mentions external world skeptics directly, let alone why they have a hard time refuting Moore’s position.
Choice C
Choice C is incorrect. We can’t infer that the author of Text 1 would respond this way to external world skeptics. Text 1’s presentation of Moore’s concept of common sense only includes the idea that some facts are true based on instinct—it doesn’t mention the idea that some proofs are inadequate based on instinct.