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

Action Reasoning:
To move towards the goal state, we need to stack block 'a' on block 'c'. First, we must pick up block 'a' from the table since it is clear and the hand is empty.

New State Description:
The hand is holding block 'a'. Block 'c' remains on the table and clear. Block 'b' is on the table with block 'd' on top of it. Block 'd' is on block 'b' and is clear. The diagram now shows block 'a' being held by the hand.

Action Chosen:
pick-up(a)
