Answer: The right answer is the B) Paragraph 4.
Explanation: Just to elaborate a little on the answer, it can be added that paragraph 4 is the one that contains a significant amount of specific and factual information, primarily data, that wouldn't be easily paraphrased (written using one's own words), and, therefore, should be cited. The information contained in the other paragraphs could be more easily paraphrased, so it would not have to be cited.