ANS:A - isothermal expansion

In an isothermal expansion process, there is an increase in entropy with no degradation of energy. During an isothermal expansion, the temperature of the system remains constant. As the gas expands, its volume increases, and since the temperature is constant, the internal energy of the gas remains unchanged. However, because the gas expands into a larger volume, the number of microstates available to the gas molecules increases, leading to an increase in entropy. The increase in entropy occurs without any degradation of energy because the process is reversible and occurs at constant temperature. This means that the energy is conserved, and no energy is lost as heat or work during the expansion. Therefore, the increase in entropy reflects the dispersal of energy into a larger number of microstates, resulting in a more disordered system without any loss of energy.