1. (5 points) Below is the set basic robot actions: pickup(x):- P&D:ontable(x),clear(x), handempty A: holding(x) putdown(x):- P&D: holding(x) A: ontable(x), clear(x), handempty stack(x, y):- P&D: holding(x), clear(y) A: handempty, on(x,y), clear(x) unstack(x, y):- P&D: handempty, clear(x), on(x,y) A: holding(x), clear (y) a) Define how the two STRIPS rules, pickup(x) and stack(x,y) could be combined into a macro-rule 'put(x,y)'. b) What are the preconditions, delete list, and add list of the new rule?