Please do C and D

2. (40 pts) Consider the transitivity of the biconditional: (( PQ) (QAR)) ( PR). a. Show that this argument is valid by deriving a tautology from it, a la section 2.1. You may use logical equivalences (p. 35), the definition of biconditional, and the transitivity of conditional: ((PQ) ( QR)) ( PR). b. Show that this argument is valid using a truth table. Please circle the critical lines. c. Write the premise of the argument, (( PQ) ( QR)), in disjunctive normal form. d. Draw a circuit diagram of the premise of the argument, (( PQ) ( QR)), using only 'and' or' and 'not' gates