The figure shows a plot of binding energy per nucleon $E_b$ against the nuclear mass $M$. $A, B, C, D, E, F$ correspond to different nuclei. Consider four reactions:
$(i) \, A + B \to C + \varepsilon$
$(ii) \, C \to A + B + \varepsilon$
$(iii) \, D + E \to F + \varepsilon$
$(iv) \, F \to D + E + \varepsilon$
where $\varepsilon$ is the energy released. In which reactions is $\varepsilon$ positive?

• A
  $(ii)$ and $(iv)$
• B
  $(ii)$ and $(iii)$
• C
  $(i)$ and $(iv)$
• D
  $(i)$ and $(iii)$