Parent State ID: 17
State Depth: 7
Action Taken: pick-up(a)
Action Reasoning: To achieve the goal state, block 'a' needs to be placed on block 'b'. The next logical step is to pick up block 'a' since it is clear and on the table.
State Description: Block 'a' is held in the hand. Block 'c' is on top of block 'b' and is supporting block 'd'. Block 'b' is on the table. Block 'd' is on top of block 'c' and is clear. The hand is holding block 'a'.
Action Path: ['unstack(d, a)', 'put-down(d)', 'unstack(a, c)', 'put-down(a)', 'pick-up(d)', 'stack(d, c)', 'pick-up(a)']
