If two pure liquid constituents are mixed in any proportion to give an ideal solution, there is no change in

Answer: Option C

An ideal solution is that where the components behaves like pure components.
For an ideal solution the heat of mixing or enthalpy change and volume change due to mixing is zero.
Since, volume change of mixing $$=V^t\left(T,P\right)-\sum x_i{V}_i\left(T,P\right).$$
Where $$V^t$$ $$=$$ total molar volume of the solution at temperature $$T,$$ pressure $$P.$$
$$V_i$$ $$=$$ molar volume of species when existed as pure species at same $$T,P.$$
From summability: $$V^t=\sum x_i{\stackrel{\text{lower}0.5em⌣}{V}}_l$$
Where $${\stackrel{\text{lower}0.5em⌣}{V}}_l=$$ partial molar volume since for ideal solution
$$\sum x_i{\stackrel{\text{lower}0.5em⌣}{V}}_l=\sum x_i{V}_i\left(T,P\right)\Rightarrow$$     Volume change of mixing $$=0$$
Similarly, enthalpy change of mixing or heat of mixing $$=0$$