2. Use truth tables to determine whether the following 4 argument forms are valid or not. Indicate which columns represent the premises and which represent the conclusion, and include a sentence explaining how the truth table supports your answer.

(a) p q

q p

p q

(b) p

p q

q r

r

(c) p q

p q

p r

r

(d) p q r

p q

q p

r