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

Action Reasoning:
To create the goal stack, we need to move block 'c' to the table, making it a base. Therefore, we should first unstack 'c' from 'd' and put it directly on the table.

New State Description:
The hand is holding block 'c'. Block 'b' is on the table and clear. Block 'a' is on the table. Block 'd' is on top of block 'a' and is clear. Block 'c' is no longer on block 'd' and not clear as it's in hand.

Action Chosen:
unstack(c, d)
