When do systems at different temperatures attain thermal equilibrium as time passes?

Whether the system is in an equilibrium state depends on what?

What conclusion can be drawn from the zeroth law of thermodynamics?

Given are statements for certain thermodynamic variables:
$(A)$ Internal energy,volume $(V)$ and mass $(M)$ are extensive variables.
$(B)$ Pressure $(P)$,temperature $(T)$ and density $(\rho)$ are intensive variables.
$(C)$ Volume $(V)$,temperature $(T)$ and density $(\rho)$ are intensive variables.
$(D)$ Mass $(M)$,temperature $(T)$ and internal energy are extensive variables.
Choose the correct answer from the points given below:

Why is work an extensive quantity?

Which of the following statements correctly describes the relationship between thermodynamic state variables?