Final answer:
No work is done in an isochoric process because the volume of the system remains constant, which means there is no change in volume for work to occur in a thermodynamic context. Option A is correct.
Step-by-step explanation:
In an isochoric process, no work is done because the volume of the system remains constant. Work, in thermodynamics, is defined as the product of pressure and the change in volume (W = PΔV). Since ΔV (change in volume) is zero in an isochoric process, no work is performed on or by the system, regardless of any changes in pressure, temperature, or heat added to the system. It is critical to understand that the isochoric process is characterized by maintaining a constant volume, distinguishing it from other processes like isothermal (constant temperature) or isobaric (constant pressure).
Statement A, The volume of the system remains constant, accurately explains why no work is done in an isochoric process. This is because work in thermodynamics is calculated based on changes in volume, and in the absence of such changes, work cannot occur.