A table is the most effective graphic for displaying numerical data, such as the annual income and property values of billionaires. It allows for organized presentation of data, making it easy for readers to compare figures across different individuals. Each billionaire's income and property value can be listed in rows and columns, facilitating quick visual comparisons. Other options, such as a timeline, are not suitable as they are designed to show changes over time rather than static data. A photograph cannot convey numerical information, and while a diagram might illustrate relationships, it would not present the specific financial data clearly.