Thanks for the question! So this is a pretty short stimulus: studies basically show that despite what you might think, middle-aged people are more scared of dying than elderly people. We’re looking for something that WON’T explain this phenomenon. So four of the answer choices will help explain, and one of them won’t.
So now let’s take a look at (C), which tells us that many people who suffer from depression first become depressed in middle age. Well, what’s the link between depression and fear of dying? Nothing in the stimulus tells us that the first stage of depression could lead one to fear death acutely, and we can’t just assume that. Even if that’s true based on your outside knowledge, remember, we can’t use that kind of outside knowledge on the LSAT! And remember, “many” just means “some,” which means “at least one.” So does this really explain the phenomenon of middle-aged people being more scared of dying? Not really. And we also don’t even know if middle-aged people are more likely to be depressed than elderly people. So nothing really adds up here, and (C) doesn’t explain, so it’s the correct answer here.
Hope this helps! Feel free to ask any other questions that you might have.