A propositional knowledge-base KB consisting of five sentences is given below (note that "/\" is used to denote "logical and", and "\/" is used to denote "logical or", and "~" is used to denote "logical negation"): 1. (-P / -Q) -> R 2. R-> S 3.-S 4. P -> ~U 5. U (a). (10 marks) Explain in English (in Steps!) that KB | = Q. (b). (10 marks) Show resolution steps that leads to KB |- Q. You should first convert the sentences in the KB into clauses.