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

Action Reasoning:
To progress towards the goal state, we need block 'b' on top of block 'c'. Since both blocks are clear and the hand is empty, we can pick up block 'b' first.

New State Description:
Block 'a' is on top of block 'd', block 'c' is clear and on the table, block 'b' is held in the hand, and block 'd' is supporting block 'a'. In the diagram, block 'b' is no longer on the table, and the hand is holding block 'b'.

Action Chosen:
pick-up(b)
