C is the proper answer to this which refers to the histogram. There are different types of charts that are available right now and they are meant to be used for various purposes. There are some that are well-known to people who use graphs all the time. Some people are only familiar with a select few. A histogram is known to be accurate and it can provide the information about the frequency that is needed by the person creating and analyzing the chart.
It may sometimes be mistaken as a bar graph because of its appearance but the bar graph has to compare two variables and their effect with each other. A histogram only makes use of one variable and takes note of the frequency of the variable.