Step 1: See the shape of the statement.
The statement is $(p\land q)\rightarrow(\sim p\lor r)$. This is an "if then" of the form $A\rightarrow B$, where $A=(p\land q)$ and $B=(\sim p\lor r)$.
Step 2: Recall how to negate an "if then".
The negation of $A\rightarrow B$ is $A\land\sim B$. In words, "it is not true that A leads to B" means "A is true but B is false".
Step 3: Apply that rule.
\[ \sim\big[(p\land q)\rightarrow(\sim p\lor r)\big]\equiv (p\land q)\land\sim(\sim p\lor r). \]
Step 4: Negate the "or" part with De Morgan.
De Morgan's law says $\sim(X\lor Y)\equiv\sim X\land\sim Y$. So \[ \sim(\sim p\lor r)\equiv\sim(\sim p)\land\sim r\equiv p\land\sim r. \]
Step 5: Put it back together.
\[ (p\land q)\land(p\land\sim r). \]
Step 6: Simplify the repeated $p$.
Since everything is joined by "and", and $p\land p\equiv p$, we drop the extra $p$: \[ p\land q\land\sim r. \]
Step 7: Match the option.
This is $p\land q\land(\sim r)$, which is option (4).
\[ \boxed{p\land q\land(\sim r)} \]