Symbolize and use a truth table to check the following sentence to see whether it is contingent, tautological or contradictory: If the liar does what he says and says that he does (do what he says) then the liar doesn't do what he says.
a. It is tautological.
b. It is contingent.
c. It is contradictory.
d. It can't be checked because it is versimilitudinous.