Which of the following best describes a bar graph?

A bar graph is effectively utilized to illustrate frequencies of different categories. In a bar graph, each bar represents a category, and the length or height of the bar corresponds to the frequency or count of items within that category. This makes it easy to compare different categories at a glance, as the visual representation allows for quick assessments of which categories have higher or lower frequencies.

The other options refer to different types of data representations. While A pertains to pie charts, which depict how segments of a whole relate to one another, B describes line graphs that track data points over time or across a range. D relates more to dual-axis graphs or line graphs that show the relationship between two variables across a timeline. In contrast, a bar graph specifically focuses on comparing discrete categories rather than continuous data or relationships between multiple variables.