As noted in your assignment prompt, you are able to choose which citation style you would like to use for this paper. JUST BE CONSISTENT! If you chose Chicago, stick with Chicago throughout your paper and all other assignments for this class. This page contains information on the major different citation styles.
Do not plagiarize! If you are concerned or are not sure what counts as plagiarism, check out our handy guide Plagiarism: Don't Let It Happen to You! for definitions and tips for avoiding plagiarism.
APA (American Psychological Association) style is commonly used in the social sciences. The APA released a 6th edition of their publication manual in 2010, which contains many updates from the previous edition.