Parent State ID: 16
State Depth: 7
Action Taken: pick-up(c)
Action Reasoning: To achieve the goal state, block `d` needs to be on top of block `b`, and block `a` on top of block `d`. The first step is to clear block `b` by removing block `c`. Since block `c` is clear, I will pick it up.
State Description: Block `a` is on the table and clear. Block `b` is on the table and clear. Block `c` is in the hand and not clear. Block `d` is on the table and clear. The hand is holding block `c`.
Action Path: ['unstack(d, a)', 'put-down(d)', 'unstack(a, c)', 'put-down(a)', 'unstack(c, b)', 'stack(c, b)', 'pick-up(c)']

INACTIVE REASON: deactivated because diagram generation failed or invalid action chosen: `block_c` is not on the table, violating the precondition for `pick-up`.
