5according to a new study published in july 2003 by doctor hillary anderson in the new england journal of medicine, drinking tea regularly has many health benefits. the above source information appears as a(n) a. index keyword. b. internal citation. c. works cited citation. d. footnote.

The answer you are wanting is "Internal Citation" aka "In-text Citation". We can pretty much rule out the others!

A work cited citation I think is just a work cited page, which is not where a quote would be written, it just has the information for where a person can find out more info on the subject using the links you used! 

Its not a index keyword (Look up the meaning for it and you will be able to tell! 

And lastly, it is not a footnote! Again, just look it up and click "images" to see this is not the answer! 

Hope this helps