Final answer:
The Record Source property of a form designates the table or query that serves as the foundation for the form's data display.
Step-by-step explanation:
The Record Source property of a form indicates the table or query from which the form is designed to display data. In other words, it determines from which underlying data source the form retrieves its records. This could be a single table or a result of a complex query that brings together data from multiple tables.
Answering the student's question, the correct option would be: C. The table or query the form is built upon.