What feature in QuickBooks allows you to track income and expenses by project?

The correct choice, which focuses on job costing, is designed specifically to allow businesses to track income and expenses associated with specific projects or jobs. This feature is vital for understanding the profitability of individual projects, enabling users to allocate costs accurately and analyze how much revenue each project generates compared to its expenses.

Job costing provides detailed financial insights by categorizing expenses directly related to a project, helping businesses to monitor their budget and make informed financial decisions. It not only enhances project profitability analysis but also aids in estimating future projects based on historical data.

Other options may relate to broader categories of tracking financials, but only job costing specifically focuses on the relationship between costs and income at the project level, making it integral for businesses looking to assess project-based performance effectively.