Which one of following pairs of aqueous solution will not be isotonic at same temperature?

For solution to be isotonic, ${\mathrm{\Pi }}_1={\mathrm{\Pi }}_2$ of $i_1{c}_1=i_2{c}_2$ 

In the option D,

 $i_1{c}_1=3;i_2{c}_2=2$

Here,

$i_1{c}_1\mathit{\not\equiv }{i}_2{c}_2$

Thus aqueous solution in this case will not be isotonic at same temperature.