A system is said to be thermodynamically stable if the system is in:
Thermal and Chemical equilibrium only
Thermal equilibrium only
Thermal and Mechanical equilibrium only
Thermal, Chemical, and Mechanical equilibrium
A system in which the macroscopic properties do not undergo any change with time is called thermodynamic equilibrium.
Here in Thermal equilibrium Temperature is the macroscopic property, whereas in Mechanical equilibrium Pressure is the macroscopic property and in Chemical equilibrium chemical composition is the macroscopic property.
Hence all three equilibriums are needed for the system to be in thermodynamic equilibrium.
Hence, option number (4) is correct