(p∧~q)∧(~p∧q) is
a tautology
a contradiction
neither a tautology nor a contradiction
None of these
(p∧~q)∧(~p∧q) ≡(p∧~p)∧(~q∧q) ≡f∧f ≡f (By using associative laws and commutative laws)
Therefore, (p∧~q)∧(~p∧q) is a contradiction.