A is the most suitable answer, although all of the answers are technically correct. B, C and D all serve to add <em>clarity</em> to an essay, which in turn adds interest. A directly adds interest, and the clarity comes as a secondary effect.
I believe it is D because it is talking about how it causes all these bad things which is why you need to start streaming it like a treat
hope it helped
In my dictionary (my brain), reckless means causing trouble nonstop. But you should look it up for a more accurate answer.
Hope I helped!
The best option to chose is B