Resistance increases linearly with length ($R \propto l$).

Resistance decreases as cross-sectional area increases ($R \propto \frac{1}{A}$).

Resistivity ($\rho$) is a property of the material and does not change with geometry.

Predictable circuit behavior

Uniform current distribution in homogeneous materials

Resistance changes with temperature ($\alpha$ coefficient)

Skin effect at high frequencies reduces effective cross-sectional area

Resistor manufacturing

Power transmission lines design

Option B is incorrect because $R \propto \frac{1}{A}$.

Option C is incorrect because $R$ is directly, not inversely, proportional to length.

Option D is incorrect because $R$ is directly proportional to resistivity ($\rho$).