The negative of $q\; \vee \sim (p \wedge r)$ is

The contrapositive of the statement "If it is raining, then I will not come", is

Let $p$ and $q$ denote the following statements
$p$ : The sun is shining
$q$ : I shall play tennis in the afternoon

The negation of the statement "If the sun is shining then I shall play tennis in the afternoon", is 

If $p, q, r$ are simple propositions, then $(p \wedge q) \wedge (q \wedge r)$ is true then

Which one of the following Boolean expressions is a tautology?

Consider the following three statements :

$(A)$ If $3+3=7$ then $4+3=8$.

$(B)$ If $5+3=8$ then earth is flat.

$(C)$ If both $(A)$ and $(B)$ are true then $5+6=17$. Then, which of the following statements is correct?