Which type of form validation helps in improving user experience by preventing errors during input?

The correct choice is global form validation rules, as they play a crucial role in improving user experience by ensuring that the data entered into forms meets predefined criteria before submission. These rules can prompt users in real time to correct their inputs if they do not conform to expected formats or requirements, such as an invalid email address or missing mandatory fields. This immediate feedback reduces the chances of submission errors and prevents frustration, leading to a smoother interaction and higher completion rates for forms.

While other options such as mask input and progressive profiling are also valuable for user experience, global form validation rules specifically address the prevention of errors by actively checking the user’s input against established rules as they fill out the form. This proactive approach significantly enhances usability and reduces the likelihood of data inaccuracies.