Answer:
D. the year the source was published.
Explanation:
When you are writing an academic paper, you will use many other papers as a source of research. All of these works should be referenced at the end of your work, ie you should show which sources of research were used and leave references for others to find these works. In relation to these references, you should put, the author's name, the name of the work, where the work was published, which pages you used and what was the year of publication of this work.
With this, we can say that the year in each of the entries of works cited, probably refers to the year in which the source was published.
