Which option allows for grouped average sizes displayed as bubble size?

The option that allows for grouped average sizes displayed as bubble size is a bubble chart design. Bubble charts are specifically designed to represent three dimensions of data in a two-dimensional space, where the position of each bubble on the horizontal and vertical axes represents two of the dimensions, while the size of each bubble corresponds to the value of the third dimension. This makes bubble charts particularly effective for visualizing relationships between different groups of averages, as variations in size can easily convey the differences in magnitude or importance among those groups.

In essence, bubble charts provide a clear and intuitive way to depict how average sizes vary across categories, allowing for easy interpretation and comparison. Their ability to showcase multiple variables simultaneously makes them a powerful tool in data visualization, especially when trying to highlight trends or outliers in grouped data.