Assertion: Rusting of iron is quicker in saline water than in ordinary water.
Reason: The conductivity of saline water is less than the ordinary water. 

Assertion is true but reason is false.

The correct answer is: 3. Assertion is true, but the reason is false.
Rusting of iron is indeed quicker in saline water than in ordinary water. The presence of dissolved salts in saline water provides additional ions, making the water more conductive. This increased conductivity allows for faster electron transfer during the electrochemical process of rusting. Therefore, the assertion is true.

However, the reason given is incorrect. The conductivity of saline water is actually higher than that of ordinary water due to the presence of dissolved salts. Higher conductivity facilitates the movement of electrons and ions, making the electrochemical reactions, including rusting, more rapid.