An engine runs between a reservoir at temperature $200 \mathrm{K}$ and $a$ hot body which is initially at temperature of $600 \mathrm{K}.$ If the hot body cools down to a temperature of $400 \mathrm{K}$ in the process, then the maximum amount of work that the engine can do (while working in a cycle) is (the heat capacity of the hot body is $1 \mathrm{J}/\mathrm{K})$

• A

  $200(1-\ln 2)\mathrm{J}$
• Correct answer
  B

  $200(1-\ln 3/2)\mathrm{J}$
• C

  $200(1+\ln 3/2)\mathrm{J}$
• D

  $200 \mathrm{J}$

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