An ideal gas in a cylinder is separated by a piston in such a way that the entropy of one part is $S_1$ and that of the other part is $S_2$. Given that $S_1>S_2$. If the piston is removed then the total entropy of the system will be:

• A

  $S_1\times S_2$
• B

  $S_1-S_2$
• C

  $\frac{S_1}{{ S}_2}$
• Correct answer
  D

  $S_1+S_2$

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