Which of the following is NOT a duty of district boards during elections?

The function of district boards during elections primarily focuses on ensuring that the electoral process runs smoothly and in compliance with regulatory standards. Preparing the place for voting, verifying that voters are properly registered, and returning registration books to the Municipal Clerk are all essential tasks that fall under the responsibilities of district boards.

In contrast, conducting candidate interviews is not within the scope of the district boards' duties. Candidate interviews are typically the responsibility of political party organizations, nominations committees, or similar entities involved in the election process rather than the boards responsible for managing the election logistics. Therefore, recognizing that conducting candidate interviews does not pertain to the responsibilities of district boards clarifies why this option stands out among the others, which are indeed integral to the election process.