The minimum number of switches in the simplified form of the following switching circuit is

The correct logical equivalence from the following is /are ___
(I) $p \to (q \to r) \equiv (p \wedge q) \to r$
(II) $(p \to q) \to r \equiv p \to (q \vee r)$
(III) $(p \to q) \to r \equiv (p \to r) \wedge (\sim q \to r)$
(IV) $p \to (q \to r) \equiv q \to (p \to r)$

The contrapositive of the statement pattern $[p \vee (p \to q)] \to (p \wedge \sim q)$ is

The negation of the converse of $p \vee q$ is