Option B
Solution:
(a <-> c) -> (~b -> (a˄c))
For the expression to be Tautology, T -> F should not arise. So taking a = False, c= False and ~b = True,
(~b -> (a˄c)) = False
and (a <-> c) = True
So, True -> False, scenario is arising. So option B is the correct answer.
For all other expressions, True-> False scenario will not arise.