Step 1: Recall the precedence order among these operators.
Among the four listed, the order from highest to lowest precedence is $!$ first, then $==$, then $\&\&$, then $||$ last.
Step 2: Think about why this order makes sense.
Logical NOT applies to a single value so it binds tightest, comparisons like $==$ happen next to form true/false results, then AND combines conditions more tightly than OR combines them.
Step 3: Pick out the lowest one.
Since OR is evaluated only after everything else has been resolved, it sits at the bottom of the precedence list.
\[ \boxed{||} \]