Given below are two statements: one is labelled as Assertion A and the other is labelled as Reason R
Assertion A: The binding energy per nucleon is practically independent of the atomic number for nuclear of mass number in the range 30 to 170
Reason R: Nuclear force is short ranged.
In the light of the above statements, choose the correct answer from the options given below

The binding energy per nucleon is practically independent of the atomic number for nuclear of mass number in the range 30 to 170, as it remains almost same for all the isotopes in this range.

But as the mass number increases the p/n ratio decreases, leading to increase in proton-proton interactions leading to decrease in the binding energy.

Although nuclear force is a short range force it is not the reason for the decrease in the binding energy.