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 found to be practically independent of the atomic number A, for nuclei with mass numbers between 30 and 170. Reason (R): Nuclear force is long range. In the light of the above statements, choose the correct answer from the options given below :

• Correct answer
  A

  $(A)$ is true but (R) is false
• B

  (A) is false but (R) is true
• C

  Both $(\mathbf{A})$ and $(\mathbf{R})$ are true and $(\mathbf{R})$ is the correct explanation of $(\mathbf{A})$
• D

  Both (A) and (R) are true but (R) is NOT the correct explanation of (A)

Hence, the correct answer is option: 'A'.