Final answer:
A graphing calculator is used to visualize transformations of graphs by allowing the observation of changes applied to the function, whereas rulers and protractors are used for measuring distances and angles in vector analysis.C is the correct answer.
Step-by-step explanation:
The tool used to visualize transformations of graphs is a graphing calculator. When working with transformations, such as translating, reflecting, rotating, or scaling graphs of functions, a graphing calculator allows one to input the function and then visually observe the transformation as it's applied.
In contrast, tools like a ruler or protractor are more commonly used to measure distances and angles, respectively, especially in the context of vector analysis, for example, when we need to determine the magnitude and direction of a resultant vector.
Rulers and protractors are part of graphical methods, such as the head-to-tail method, which involves drawing vectors to scale on paper and determining their resultant manually. However, for the purpose of graph transformations in a broader mathematical context, and especially in a digital environment, the correct answer in the final answer is the graphing calculator, as it provides an immediate and accurate representation of how the graph is altered by the transformation.