The correct answer choice should be C. The adverbial phrase is In complete silence. It describes HOW the test should be taken
One part is "Unless we start listening to Mother Nature and start taking care of our lush, green planet, our world as we know it will not be around much longer." It can make the reader seem worried for the planet because they live on it and it not being around much longer than where will they go? It makes them want to help for the sake of them selves. As well as "Every part of nature is being depleted by overuse and lack of care, and no one seems concerned." People don't want to be know as "the bad guys" so they want to start helping so they won't be put into the horrible people title.
To prevent from succeeding.
Essentially 3. He stated that readers minds would "require a change of diet" and that stories should be read in one sitting to "capture the essence" of it.