$\begin{array}{1 1} \text{(a) The o- isomers being more symmetrical fits closely in the crystal lattice and thus has stronger inter-molecular forces of attraction than p- and m- isomers .} \\ \text{(b) The p- isomers being more symmetrical fits closely in the crystal lattice and thus has equal intermolecular forces of attraction than o- and m- isomers .}\\ \text{(c) The p- isomers being more symmetrical fits closely in the crystal lattice and thus has weak intermolecular forces of attraction than o- and m- isomers .} \\ \text{(d) The p- isomers being more symmetrical fits closely in the crystal lattice and thus has stronger intermolecular forces of attraction than o- and m- isomers .} \end{array} $
