This question contains Statement $-1$ and Statement-2. Of the four choices given after the statements, choose the one that best describes the two statements. Statement - I: Energy is released when heavy nuclei undergo fission or light nuclei undergo fusion. and Statement - II For heavy nuclei, binding energy per nucleon increases with increasing $Z$ while for light nuclei it decrease with increasing $Z$.

• A

  Statement $-1$ is false, Statement $-2$ is true.
• B

  Statement - 1is true, Statement $-2$ is true; Statement $-2$ is correct explanation for Statement-1.
• C

  Statement $-1$ is true, Statement $-2$ is true; Statement $-2$ is not a correct explanation for Statement-1.
• Correct answer
  D

  Statement $-1$ is true, Statement $-2$ is False.

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