Correct Option: C. Violin plot
A violin plot is the most effective for this task because it combines the features of a box plot and a kernel density plot. It not only highlights the median, quartiles, and potential outliers (like a box plot) but also shows the data's probability density function (like a kernel density plot), providing a comprehensive overview of the data distribution across various categories.

Why other options are not the best choice:

• A. Line plot: While useful for displaying trends over time or continuous data, it does not provide the detailed distribution information required for this task.
• B. Scatter plot: This is ideal for examining the relationship between two continuous variables but does not offer insights into the distribution of data across categories.
• D. Box plot: Although useful for comparing distributions across categories, it lacks the detailed density information that a violin plot provides, making it less comprehensive for understanding the underlying probability density of the data.