Attempt Number: 3
Error Message: Action not unique compared to other actions chosen from this state before. Choose a new action

Action Reasoning:
We need to place block d on top of block a to achieve the goal state configuration, and currently, the hand is holding block d.

New State Description:
Block a is on top of block c and is supporting block d. Block b is clear and on the table. Block c is not clear as it is supporting block a. Block d is now clear and on top of block a. The hand is empty.

Action Chosen:
stack(d, a)
