What is the best title for the following list?

background information
explanation of a confusing topic
supporting evidence for a thesis
expert opinion on a topic
opposing evidence for a thesis

a. various audiences for a source

b. different types of propaganda

c. various purposes of a source

d. different types of bias

The correct answer is C. Various Purposes of a Source

Explanation:

An information source or source is a place, document or similar where information can be found, information sources can include all types of information that can be used for multiple purposes. In the case of texts and speeches information sources are key as it is in them the writer or speaker find support to develop the ideas, this can include background information of the topic or subject; supporting evidence such as examples, statistics or research studies; opinion or information from experts on the subject; opposing evidence to your thesis that helps you show why what you claim is valid despite the evidence against it and explanations that help you understand or explain difficult points. Thus, the most appropriate title for this list is various purposes of a source because the list is about the way information sources can be used for a speech or text, thus this title summarizes the content of the list.

c. barbarians with unexpected intelligence  

caliban is prospero's slave in the shakespear's play "the tempest"