If q is false and p q r is true, then which one of the following statements is a tautology?

Step-by-step solution

q is false and [(p q) r] is true As (p q) is false [ False r] is true Hence r is false Option (1): says p r , Since r is false Hence (p r) can either be true or false Option (2): says (p r) (p r)(p r) is false Since, F T is true and F F is also true Hence, it is a tautology Option (3): (p r) (p r) i.e. (p r) F It can either be true or false Option (4): (p r) Since, r is false Hence, (p r) is false.