ISRO2017-22

Question

Which one of the following Boolean expressions is NOT a tautology?

• A. $((a \rightarrow b) \wedge (b \rightarrow c)) \rightarrow  (a \rightarrow c)$
• B. $(a \leftrightarrow c) \rightarrow (\sim b\rightarrow (a\wedge c))$
• C. $(a\wedge b \wedge c)\rightarrow (c \vee a)$
• D. $a\rightarrow (b\rightarrow a)$

Answer 1

option B is not tautology