The correct choice is D because it clearly conveys both the setting and the mood.
The initial information to cite for a Works Cited page should be the author's name. If the author's name is unavailable, simply omit that part without leaving a placeholder. Next, you should mention the title of the source. Since this is a web source, you will need the site's title: A Day for Trees.
The complete citation would be: A Day for Trees, U.S. Department of Agriculture, 10 Jan. 2014. <web address>. Accessed 18 April 2014.
I'm not completely certain, but I believe it's option B.