9. (10 points) You are given the following set of premises and conclusion: ABCBACAC (a) Determine if the argument is invalid by writing an "IsInvalid" statement as discussed in lecture 5 and simplifying. Is the argument invalid? If the argument is invalid, explain which set of input values for A,B,C would make it invalid. (b) Determine if the argument is invalid by writing the truth table for the premises and conclusion and identifying the critical rows. How many critical rows are there in the the truth table? Is the argument valid