When a system is taken from state $i$ to state $f$ along the path $\mathrm{iaf}$, it is found that $Q=50 \mathrm{~cal}$ and $\mathrm{W}=20 \mathrm{~cal}$. Along the path' $\mathrm{ibf}$ $\mathrm{Q=36 ~cal}$. $\mathrm{W}$ along the path $\mathrm{ibf}$ is

• Correct answer
  A

  $6 \mathrm{~cal}$
• B

  $16 \mathrm{~cal}$.
• C

  $66 \mathrm{~cal}$.
• D

  $14 \mathrm{~cal}$.

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