Thomas is preparing a report on the cost of living in the seven most populous cities in the world. He decides to include a graphic that will help his readers compare the cost of living in all the seven cities. In this case, which of the following graphics will best represent the data?

A) An organizational chart
B) A flowchart
C) A bar chart
D) The Gantt chart

A bar chart is the best choice for comparing the cost of living in different cities. It allows for quick comparison of prices by displaying them as bars of different lengths on the same axis. An organizational chart and a flowchart are not appropriate for this purpose, as they are used to show relationships or processes, not numerical comparisons. The Gantt chart is also not suitable, as it is used to show timelines or schedules.