Thanks for the question! Let’s take a look at what this the stimulus tells us. We’re told that this TV documentary goes beyond some save-the-wildlife pieties and basically talks about how the elephant can be a pest. And there seems to be no way to protect East African farms from the voracious foraging of night-raiding elephant herds. So this is supposed to show something, and we have to logically complete the paragraph.
So where is this supposed to be going? Well, it basically just looks like it’s calling our attention to the fact that elephants aren’t actually these great things we need to save, they can actually be pests. And that’s probably how we should complete the stimulus. (A) fits perfectly in line with that, since it tells us that the example illustrates that the preservation of wildlife may endanger human welfare. Since the farms can’t be protected from the herds, that’s a great illustration of the fact that elephants can be dangerous to human welfare! And that’s what makes (A) the correct answer.
Hope this helps! Feel free to ask any other questions that you might have.