Water can dissolve more substances than any other liquid because

1. A

   it is dipolar in nature

   Dipolar. Water’s polarity lets it solvate ions and polar molecules — the ‘universal solvent’ reason.

2. B

   it is a good conductor of heat

   Heat conductor. Not why it dissolves salt.

3. C

   It has high value of specific heat

   High specific heat. A climate property, not solvent power.

4. D

   It is an oxide of hydrogen

   Oxide of hydrogen. True chemistry, not the solvent explanation.

Summary. Official key is (a). Water dissolves more substances than most liquids because the molecule is polar (dipole) and hydrogen-bonded. Conductivity, specific heat and being H2O do not explain that solvent range.