Points on a budget constraint all share which property?

1. The line marks the boundary of what is affordable. 2. Each point on the budget constraint represents a combination of goods whose total cost adds up to the budget. 3. In the worked example that budget is 10 dollars. 4. Spending less would place the choice inside the line rather than on it. _Source: OpenStax Principles of Microeconomics for AP(R) Courses 2e (CC BY 4.0), Ch 2 'Choice in a World of Scarcity', sections 2.1-2.3_