Let A = p ↔ [q ^ (~ r -> p)].
(a)Construct a truth table for the expression A. Hence determine whether the
expression A is a tautology, contradiction, or contingency.
(b) Obtain the Principal Disjunctive Normal Form (PDNF) and Principal
Conjunctive Normal Form (PCNF) of A. Hence, deduce the PDNF and PCNF