Contrapositive of the statement 'If two numbers are not equal, then their squares are not equal', is

If $P$ and $Q$ are two statements, then which of the following compound statement is a tautology?

Which of the following is an open statement

The statement $\sim[p \vee(\sim(p \wedge q))]$ is equivalent to

Which one of the following is a tautology ?

Statement $-1$ : The statement $A \to (B \to A)$ is equivalent to $A \to \left( {A \vee B} \right)$.

Statement $-2$ : The statement $ \sim \left[ {\left( {A \wedge B} \right) \to \left( { \sim A \vee B} \right)} \right]$ is a Tautology