Attempt Number: 2
Error Message: Action not unique compared to other actions chosen from this state before. Choose a new action

Action Reasoning:
To move closer to the goal state, unstacking `a` from `c` will allow us to stack `a` on `d` later, which is needed for the final configuration.

New State Description:
Block `a` is now in the hand, no longer clear, and not on block `c`. Block `c` is clear and on top of block `b`. Block `b` is on the table. Block `d` is on the table and clear. The hand is holding block `a`.

Action Chosen:
unstack(a, c)
