You only need to include a site's URL if the web page is difficult to find or if your instructor requires you to include a URL.
Explanation
Choice A: There is no site sponsor included. Choice B: There is incorrect capitalization in the title. Choice C: There is no date of access at the end of the citation.
Choice B: The title is not capitalized correctly. Choice C: This is an APA citation for the book. Choice D: There is no format (medium) at the end of the citation.
Hohn, Donovan. Moby Duck: The Story of 28,800 Bath Toys Lost at Sea, and of the Beachcombers, Oceanographers, Environmentalists, and Fools--Including the Author--Who Went in Search for Them. New York: Viking, 2011.
Doyle, Denis. "You Say Tomato, I Say Duck!" Life Nov. 1995: 20-21. Academic Search Complete. Web. 5 Oct. 1998.