The true statement amongst the following is:

🧠 Both $S$ and $\Delta S$ depend on temperature — entropy is not a constant Absolute entropy $S$ is defined via $S = \int_0^T \frac{C_p}{T}\,dT$, which clearly depends on $T$. Entropy change $\Delta S = \sum S^\circ(\text{products}) - \sum S^\circ(\text{reactants})$ — since each $S^\circ$ depends on $T$, so does $\Delta S$.

Options (b), (c), (d) all claim that either $S$ or $\Delta S$ is independent of temperature — all three are wrong.

Only (a) is correct: both $S$ and $\Delta S$ are functions of temperature.

⚠️ Trap: Students sometimes think $\Delta S$ is constant because $\Delta H$ and $\Delta G$ are often tabulated at 298 K. Those are just reference values — both entropy quantities change with temperature in general.

$\boxed{\text{Answer: (a)}}$