Final answer:
The Supreme Court has ruled that race cannot be the predominant factor in drawing congressional districts, and states are allowed to use unelected, nonpartisan commissions for redistricting. These rulings are part of efforts to curb the practice of gerrymandering.
Step-by-step explanation:
The subject of redistricting and its legal rulings fall under the category of elections and redistricting in the field of Social Studies. Regarding the options presented in the question, it is race cannot be the predominant factor in drawing congressional districts, which is consistent with the Supreme Court's stance on the matter. The Court's ruling emphasizes that district lines should not be drawn predominantly based on racial considerations but should comply with the Voting Rights Act, ensuring that minority groups' voting strength is not diminished.
Regarding the creation of independent state commissions, the Supreme Court has ruled that states can use unelected, nonpartisan committees to draw congressional districts as seen in the case of Arizona State Legislature v. Arizona Independent Redistricting Commission (2015). This ruling supports the notion that gerrymandering, the manipulative drawing of district boundaries, can be addressed through such commissions to ensure fairer and less partisan-driven redistricting processes.