Final answer:
The Constitution's full faith and credit clause requires states to respect each other's legal documents and judicial decisions, facilitating interstate relations and ensuring consistency across state lines (option c).
Step-by-step explanation:
The Constitution's full faith and credit clause is found in Article IV, Section 1 of the U.S. Constitution. It mandates that each state must honor and respect the public acts, records, and judicial proceedings of every other state. This clause is crucial for maintaining legal consistency and ensuring that documents such as contracts and court decisions are recognized across state lines, thereby facilitating interstate relations.
For example, if a person signs a car loan in one state, they are obliged to fulfill the terms of that loan even if they move to another state. Likewise, a driver's license issued by one state must be honored by other states. The clause also had significant implications for recognizing out-of-state same-sex marriages prior to their legalization at the federal level.
Hence, the answer is option c.