What must the active player announce for each attacking creature blocked by multiple creatures during the declare blockers step?

When a player declares blockers for an attacking creature that is blocked by multiple creatures, the active player must announce the damage assignment order for that creature. This is an important rule because it determines how damage will be assigned among the blocking creatures during the combat damage step.

In situations where an attacking creature is blocked by multiple creatures, the defending player has the opportunity to assign damage to those creatures in the order that they choose. This order can have strategic implications, especially if the blocking creatures can potentially be destroyed based on the amount of damage assigned. Therefore, announcing the damage assignment order clearly communicates to all players how the damage will be resolved, ensuring that the combat interactions proceed smoothly and without confusion.

The other choices do not pertain to the necessary announcement made during the declare blockers step. "Blockers" refers to the action already completed when blockers are declared, "defending player" is not an action that requires announcement during this phase, and "combat damage" itself is resolved later in the combat damage step rather than being announced. Thus, the requirement to announce the damage assignment order is crucial for clarity and adherence to the rules during combat interactions.