Final answer:
The source of law that ensures consistency in court decisions is Common Law (c), which relies on the principle of stare decisis, guiding judges to follow established precedents.
Step-by-step explanation:
The source of law that ensures the same principle applied in one court decision is used to make future legal determinations is c) Common law.
Common Law, also known as case law or precedent, is developed by judges through court decisions. This system emphasizes the principle of stare decisis, which means 'to stand by things decided'. Under this principle, courts are expected to adhere to established precedents when ruling on cases, fostering consistency and stability in legal decisions.
This legal doctrine is key in maintaining the integrity and predictability of the judicial system, as it ensures that similar facts in cases are treated in the same manner, unless there is a compelling reason for the courts to deviate from precedent.