Which control allows for enhanced user interaction within a form by grouping related fields?

The fieldset element is specifically designed to group related fields within a form, enhancing user interaction and making forms more organized and easier to understand. By using fieldsets, developers can visually separate and categorize related inputs, such as grouping all the fields related to user contact information or personal details. This clear structure aids users in navigating the form, as they can quickly identify which fields belong together and understand how they relate to the overall purpose of the form.

Additionally, fieldsets can often be accompanied by a legend element, which provides a caption or title for the grouped fields, further improving the clarity and usability of the form. This combination emphasizes the logical connection between grouped items, which can lead to a more efficient user experience.

The other options provided serve different purposes. Textfields are used for individual text input, checkboxes are for selecting multiple options among presented choices, and radio buttons allow users to select a single option from a set. None of these options provide the same functionality of grouping fields, which is essential for enhancing user interaction in a form context.