Solve this:

Q.   If P$°$ and P are the vapour pressure of solvent and solution, n₁ and n₂ are the moles of solute and solvent, then

$$\begin{gathered} \left(1\right) \mathrm{P}° = \mathrm{P}\left(\frac{{\mathrm{n}}_2}{{\mathrm{n}}_1 + {\mathrm{n}}_2}\right) \left(2\right) \mathrm{P} = \mathrm{P}°\left(\frac{{\mathrm{n}}_2}{{\mathrm{n}}_1 + {\mathrm{n}}_2}\right) \\ \left(3\right) \mathrm{P}° = \mathrm{P}\left(\frac{{\mathrm{n}}_1}{{\mathrm{n}}_1 + {\mathrm{n}}_2}\right) \left(4\right) \mathrm{P}° = \mathrm{P} \times {\mathrm{n}}_1 \end{gathered}$$