Attempt Number: 2
Error Message: Action not unique compared to other actions chosen from this state before. Choose a new action

Action Reasoning:
The next best action is to stack(c, b) because it places block C on block B, achieving the goal state where block B is below block C.

New State Description:
Block c is on block b and clear. Block b is no longer clear. Block a is on the table and is clear. Block d is on the table and is clear. The hand is empty.

Action Chosen:
stack(c, b)
