#linear-planning

Question 1: Single choice

In the Sussman anomaly, block C is on A, A and B are on the table, and the goal is on(A, B) ∧ on(B, C). What goes wrong for a linear planner that achieves the two subgoals one after the other?

Whichever subgoal it achieves first, achieving the second one undoes it1
Neither subgoal can be achieved on its own, starting from the initial state2
The goal is unreachable, so every planner fails on it3
It succeeds only if it achieves on(B, C) before on(A, B)4

Timed test