Given below are two statements: One is labelled as Assertion (A) and the other is labelled as Reason (R)

Assertion (A) : Enthalpy of neutralisation of strong monobasic acid with strong monoacidic base is always $-57 \mathrm{~kJ} \mathrm{~mol}^{-1}$

Reason (R) : Enthalpy of neutralisation is the amount of heat liberated when one mole of $\mathrm{H}^{+}$ ions furnished by acid combine with one mole of ${ }^{-} \mathrm{OH}$ ions furnished by base to form one mole of water.

In the light of the above statements, choose the correct answer from the options given below.

1. A (A) is true but (R) is false
2. B Both (A) and (R) are true and (R) is the correct explanation of (A) Correct answer
3. C Both (A) and (R) are true but (R) is not the correct explanation of (A)
4. D (A) is false but (R) is true