Parent State ID: 9
State Depth: 3
Action Taken: pick-up(block_d)
Action Reasoning: To achieve the goal state, block D needs to be on block C. Since block D is clear and on the table, the best next action is to pick up block D.
State Description: Block A is on the table and clear. Block B is on block C and clear. Block C is on the table but not clear as it supports block B. Block D is held by the hand and not clear. The hand is holding block D.
Action Path: ['unstack(block_b, block_c)', 'stack(block_b, block_c)', 'pick-up(block_d)']

INACTIVE REASON: action path invalid: The action pick-up(block_d) is invalid because it violates its preconditions: block_d is not clear, block_d is not on the table, and the hand is not empty. The current state's description and visualization are accurate, but the action itself is not logical.
