Answer: newspaper
Explanation:
Generally speaking, if you are undertaking reading for your assignments you will focus on peer-reviewed journal articles, books and reputable websites. Depending on your course of study you may also have to read other official material such as law cases, government papers, conference papers, policy documents etc.
Even apparently non-academic written sources such as newspapers, blogs, leaflets, social media feeds etc can be used in academic work as long as you are using them appropriately (e.g. to gauge or demonstrate public opinion rather than as an authoritative voice).
Academic sources do not have to be written texts, again depending on your course of study, you may need to refer to images, artwork, maps, film, TV broadcasts, music, podcasts, live performances etc. What is important is that you are able to use these sources critically, showing that you understand when to use them and why.
Newspapers may have a remit to inform but they have, and have always had, very different political and social agendas. The intended audience and the reporters'/editors' purposes in writing the articles can greatly affect their content. What are introduced as 'facts' to back up arguments can be extremely selectively chosen and you need to take this into account.
Some sources are more reliable than others but they may still involve a great deal of bias. Generally, the broadsheet newspapers are more reliable than the tabloids but they too will spin information to meet their own agendas. Newspaper articles are good ways of evidencing public opinion and for historians they offer a unique insight into some time periods - as long as they are not used as the only source of information.