An ideal solution is prepared from $117\mathrm{g}$ of benzene (molar mass $78$) and $46\mathrm{g}$ of toluene (molar mass $92$). At the temperature of interest the pure vapour pressures are $120\mathrm{torr}$ (benzene) and $40\mathrm{torr}$ (toluene). The total vapour pressure is

1. A$80\mathrm{torr}$
2. B$60\mathrm{torr}$
3. C$160\mathrm{torr}$
4. D$100\mathrm{torr}$