Which of the following sentences in a research paper should include a citation?

Question

Quizplus · Accepted Answer

Writers need to include citations when using data, ideas, images, etc. that are not their own (including paraphrasing of ideas). Information that would not be considered common knowledge should also receive citations for its source. In this example, the writer wants to use Sidney Tarrow's idea in his/her own writing, so it would need a citation. 
This paper focuses on the role of the already existing social networks in order to understand the origins of the protests. This sentence does not require a citation, as it is introducing a paper, not using someone else's ideas or information.
During the whole summer, the protests in the little Italian region were all over the news. This sentence does not need a citation, as it is simply sharing an event that took place and is not using someone else's ideas or information.
Taking into account the Sidney Tarrow's arguments previously exposed, this paper concludes that the political context played a key role in last summer's protests. This sentence does not require a citation, as the author is drawing his/her own conclusion about the protests, referencing Sidney Tarrow's arguments (which does not include a specific idea or information that needs to be cited in this case).

Which of the Following Sentences in a Research Paper Should