What setting enables one to ensure respondents complete required questions in a Qualtrics survey?

The correct choice, which pertains to ensuring respondents complete required questions in a Qualtrics survey, is Response Validation. This feature is crucial because it allows the survey creator to set specific rules that necessitate responses to certain questions before the survey can progress. For instance, you can mark a question as "required," which will prompt respondents to answer it before moving on to the next section of the survey. This helps maintain data integrity by ensuring that important information is collected without any gaps.

In contrast, Survey Preview allows the creator to see how the survey looks before it is distributed but does not enforce completion of questions by respondents. Sample Testing is commonly used to assess a survey's effectiveness or gather feedback on the design and flow, but it doesn't interact with respondents in the way that ensures required questions are completed. Data Export Settings pertain to how collected data can be exported after the survey is completed, but these settings do not influence whether questions are answered during the survey itself.