The expression $((p \wedge q) \vee (p \vee \sim q)) \wedge (\sim p \wedge \sim q)$ is equivalent to

Consider the following three statements:
$(A)$ If $3+2=7$ then $4+3=8$.
$(B)$ If $5+2=7$ then earth is flat.
$(C)$ If both $(A)$ and $(B)$ are true then $5+6=11$.
Which of the following statements is correct?

The negation of the statement "If a quadrilateral is a square,then it is a rhombus" is:

Negation of the statement $(p \vee r) \Rightarrow (q \vee r)$ is :

Check the validity of the statement given below by the method specified against it.
$p:$ The sum of an irrational number and a rational number is irrational (by contradiction method).

$(S1) (p \Rightarrow q) \vee (p \wedge (\sim q))$ is a tautology. $(S2) ((\sim p) \Rightarrow (\sim q)) \wedge ((\sim p) \vee q)$ is a contradiction. Then