Parent State ID: 46
State Depth: 7
Action Taken: unstack(block_b, block_c)
Action Reasoning: To align with the goal state, block D needs to be stacked on block C. Since block B is currently on block C, we need to clear block C by removing block B first. The hand is empty, so we can use the "unstack" action to lift block B from block C.
State Description: Block A is on the table and clear. Block B is held in the hand and not clear. Block C is on the table and clear. Block D is on the table and clear. The hand is holding block B.
Action Path: ['unstack(block_b, block_c)', 'stack(block_b, block_d)', 'unstack(block_b, block_d)', 'stack(block_b, block_d)', 'unstack(block_b, block_d)', 'stack(block_b, block_c)', 'unstack(block_b, block_c)']

INACTIVE REASON: action path invalid: The last action "unstack(block_b, block_c)" is invalid because the precondition "hand is empty" is not met. The hand is already holding block_b, so it cannot unstack block_b from block_c. The current state's description and visualization are accurate, but the last action is not logical.
