Which tab group is used to modify the background of a chart that is contained in a PowerPoint presentation? Chart styles
Data
Type
Chart layouts

Chart styles

Explanation:

In PowerPoint, once you have inserted a chart (e.g a bar or pie chart), the format tab would be enabled so that you can format your chart to your taste. In this format tab, there are a bunch of tab groups such as:

(i) Chart styles: This allows you to typically change the component background colors of your chart.

(ii) Data: This contains sub-tabs that allow you to edit and select the data on your chart.

(iii) Type: This contains sub-tabs such as "Change Chart Type" which will allow you to change the type of the chart. For example if you were using a pie chart and you want to change it to a bar chart or any other chart, you can do that here.

(iv) Chart Layouts: This allows to change or modify how the selected chart is laid out.