1. Redistricting of congressional constituencies occurs a. whenever there is a major population shift b. whenever the state government calls for redistricting c. every ten years after each national census d. every twenty years regardless of population movement or the national census

The correct answer is:<br /><br />c. every ten years after each national census<br /><br />Redistricting of congressional constituencies occurs every ten years following the completion of the United States Census, which is conducted to account for population changes and ensure fair representation in Congress.