Parent State ID: 17
State Depth: 4
Action Taken: stack(block_d, block_c)
Action Reasoning: To progress towards the goal state, block D should be placed on block C, which is currently clear. This action sets up the necessary base for stacking block B on block D, which is a step closer to achieving the desired stack order.
State Description: Block A is on the table and clear. Block B is on block C and clear. Block C is on the table and not clear. Block D is on block C and clear. The hand is empty.
Action Path: ['unstack(block_b, block_c)', 'stack(block_b, block_c)', 'pick-up(block_d)', 'stack(block_d, block_c)']

INACTIVE REASON: deactivated because diagram generation failed or invalid action chosen: Block C is not clear, violating the precondition for stacking.
