In data validation, which description best captures a format check?

• A. It validates that the data is of the expected type.
• B. It verifies that the data is present.
• C. It ensures the data matches a specific pattern, such as a phone number.
• D. It checks that the data length is within bounds.

Answer: (C)

A format check focuses on the shape of the input—the pattern or structure it must follow. It ensures the data matches a defined pattern, such as a phone number that has digits in certain positions and may include specific separators or a country code. This goes beyond simply being a number or a string, and beyond merely being present or having the right length. The key idea is that the value must conform to a specific format, typically enforced with a pattern like a regular expression.