Let U= {4,5,6,7,...,20). Consider the following propositions over U: p(x): x is prime q(x): x 12 r(x): x= 5n 1 for some n E Z. What are the truth set of the following propositions? a) p b) q c) r d) ~p e) q v~p f) ~(pvr) g) r p h) Are any of these parts a) through e) tautologies or contradictions? Comment on why or why not.