Recall the definitions of each concentration term

• Molality $m$: $m = \frac{\text{moles of solute}}{\text{mass of solvent in kg}}$

• Molarity $M$: $M = \frac{\text{moles of solute}}{\text{volume of solution in L}}$

• Mole fraction of a component: $x_i = \frac{n_i}{\sum n_i}$

• Mass percentage: $\%\,\text{by mass} = \frac{\text{mass of component}}{\text{total mass of solution}} \times 100$

Check which quantity depends on temperature

Temperature mainly affects volume due to thermal expansion or contraction.

• Molality depends on mass of solvent, and mass does not change with temperature. So, molality is temperature independent.

• Molarity depends on volume of solution, and volume does change with temperature. So, molarity changes with temperature.

• Mole fraction depends only on number of moles, not volume. So, it is temperature independent.

• Mass percentage depends on masses, not volume. So, it is temperature independent.

Evaluate the options

• A: Molality — Incorrect
• B: Molarity — Correct
• C: Mole fraction — Incorrect
• D: Mass percentage — Incorrect

Final answer

The quantity which changes with temperature is: $\boxed{\text{Molarity}}$