The correct answer is C. A graph
Step-by-step explanation:
A research paper is a type of academical paper in which your report the process you followed for doing research which in most cases implies looking for information to answer a particular question or understanding a subject. Considering the research process is a complex process that integrates multiple steps and contents it is common research paper uses images, graphs, charts, quotes, and other tools that help the author explain ideas better in the research paper.
In the case of graphs, these are visual tools that allow the author to show the relation between two aspects or variables that are usually measured in numbers, due to this, graphics are used to show the differences of one variable over time. Considering this, if you need a visual that compares the way temperatures change over time in a city the best visual you can use is a graph as this would allow you to show visually clearly the differences of temperatures by relating the year or month to the temperature registered and because the information you need to illustrate is mainly numerical information and graphs are useful in this case.