How many justices must agree to hear a Supreme Court case?

To hear a Supreme Court case, the agreement of four justices is required, commonly referred to as the "rule of four." This rule allows a minority of justices to grant a writ of certiorari, meaning they can decide to review a case, even though a majority may not yet be convinced of its merit. This system ensures that important legal questions can be addressed by the Court even if all justices are not initially in agreement. The rule of four promotes wider access to the Court for cases that may have significant implications for law and society.

The other options suggest a different number of justices, which does not align with the established practice of the Supreme Court. For instance, five justices or more would create a situation where the majority must support the decision to hear the case, which would conflict with the policy designed to allow justices to bring forward cases of importance without needing a majority consensus.