Attempt Number: 4
Error Message: Action not unique compared to other actions chosen from this state before. Choose a new action

Action Reasoning:
The hand is empty, and block c is clear and on top of block d. We can unstack c from d to start rearranging the blocks to match the goal state.

New State Description:
The hand is holding block c. Block d is now clear and on top of block a. Block a is on the table. Block b remains on the table and clear. Block c is no longer on block d and is held by the hand.

Action Chosen:
unstack(c, d)
