Explanation:

• Option A (Tree-map): Incorrect. A tree-map is primarily used for displaying frequency distributions or hierarchical data, where the area of each rectangle represents the value of a group. It is not designed to illustrate correlations between variables.

• Option B (Scatter plot): Correct. A scatter plot is an effective graphical tool for visualizing the relationship between two numerical variables. It plots individual data points on a two-dimensional plane, making it ideal for identifying trends, patterns, or correlations between the variables.

• Option C (Clustered bar chart): Incorrect. A clustered bar chart is useful for comparing frequency distributions across categories, particularly for categorical data. However, it does not provide insights into the correlation between two variables.