Assertion: Is the combustion of all organic compounds an exothermic process? Reason: Is the enthalpy of all elements in their standard state zero?
1. Both assertion and reason are true, and reason is the correct explanation of the assertion.
2. Both assertion and reason are true, but reason is not the correct explanation of the assertion.
3. Assertion is true, but reason is false.
4. Assertion is false, but reason is true.
