Final answer:
The notification to a user that an invalid choice has been made by a program is known as input validation. It ensures that the data entered by the user meets the expected criteria before being processed.
Step-by-step explanation:
When a program notifies the user that an invalid choice has been made, this is known as input validation. Input validation is a process where a program checks if the user input meets certain criteria before processing it. If the input is incorrect, the program will inform the user and may request the correct data. Examples of input validation can include checking if a user has entered a number when a number is required, or verifying that a password meets complexity requirements.