Step 1: Picture a simple experiment.
If we keep a resistor's temperature constant and steadily raise the voltage across it, we find the current rises in exact step with it, doubling the voltage doubles the current, tripling it triples the current.
Step 2: Write this pattern as a proportionality.
This kind of behaviour, where one quantity grows in direct step with another, is written as $V \propto I$.
Step 3: See where resistance fits in.
Turning the proportionality into an equation just needs a constant of proportionality, which we call resistance $R$, giving $V = IR$, but the core statement of Ohm's law is the direct proportionality itself.
Step 4: Match with the given options.
That direct proportionality between $V$ and $I$ is exactly what the first option states.
\[ \boxed{V \propto I} \]