We can use process of elimination to determine the best answer for this.
Looking at answer choice A, this would be a fantastic choice as <em>Frankenstein</em> is a frame story. A frame story is a story within a story. <em>Frankenstein</em> is a frame story because Robert Walton is told the story of the Creature and Victor by Victor, so essentially the entirety of the novel is a flashback. However, the excerpt we have here does not discuss this, so it is not the right choice.
Choice B also make a good choice as this excerpt mentions philosophers in it, however, it doesn't seem so much like a history of philosophy is being given here. It's more like the person is talking about what they did as they worked, which would have greatly interested Victor as he also has a zeal for the same things.
Choice C, while still a good option, doesn't quite fit. It talks about classification, but the excerpt doesn't refer to experiences. Based on context, it seems more likely they are classifying something scientifically.
Choice D is your best answer because it discusses the zeal previous philosophers had for learning and making connections between things. This ties in well with the overall plot line of <em>Frankenstein</em> because Victor is zealous about learning the secret to life and creating it himself.
