Option 1 - The boiling point of a solvent does not necessarily mean it will dissolve ionic salts better; thus this option is irrelevant.
Option 2 - Water is a polar molecule because it has a high dipole moment; this means it has a positive and a negative end. This polarity allows it to attract and pull apart the positive and negative ions in ionic salts, dissolving them. This is why the correct answer is option 2.
Option 3 - The high specific heat of water refers to it`s ability to absorb heat, which isn`t related to a substance`s ability to dissolve ionic salts, so it isn`t the correct choice.
Option 4 - The fact that water has no colour has nothing to do with its capability to dissolve ionic salts, so this isn`t the correct answer.