Answer is Option A
A planning graph consists of sequence of levels correspond to time steps
Used to achieve better heuristic estimates.
- A solution can also directly be extracted using GRAPHPLAN.
Consists of a sequence of levels that correspond to time steps in the plan.
- Level 0 is the initial state.
Each level consists of a set of literals and a set of actions.
- Literals = all those that could be true at that time step, depending upon the actions executed at the preceding time step.
- Actions = all those actions that could have their preconditions satisfied at that time step, depending on which of the literals actually hold.