Which of the following statement is correct regarding ignition temperature?

It is the lowest temperature at which a substance catches fire.

The correct answer is option 2. It is the lowest temperature at which a substance catches fire.

The lowest temperature at which a substance catches fire is called its ignition temperature.

For example, Kerosene oil and wood do not catch fire on their own at room temperature.

If kerosene oil is heated a little, it will catch fire. But if the wood is heated a little, it would still not catch fire. It means that the ignition temperature of kerosene oil is lower than that of wood.