1 mole of each of X1, X2 and X3, with van der Waals’ constant ‘a’ (in (atm L2mol(−2)) 1.0, 3.8 and 2.1, respectively are kept separately in three different vessels of equal volume at the same temperature. Their pressures are observed to be P1, P2, and P3 respectively. On the basis of this data alone, select the correct option (neglect the effect of ‘b’):