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

Action Reasoning:
Since block 'b' is clear and needs to be on top of block 'c' to reach the goal state, we should pick up block 'b' next.

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

Action Chosen:
pick-up(b)
