A chart is a useful way to present and display information or instructions, especially in a classroom or other educational situation. It can range in size from a large wall chart to a single piece of paper. A chart is a group of related facts presented in the form of a diagram, table, graph, or other visually organized model.
A graphic representation, as by curves, of a dependent variable, as temperature, price, etc.; graph.
Visual representations of data/numbers
There are many types of graphs such as Pie, Line, column, 3D etc.
Chart because it encompasses a graph
Both because it depends on the context