Consider the following statements:
A. Zeroth law of thermodynamics gives concept of temperature
B. First law of thermodynamics gives concept of internal energy
C. In isothermal expansion of ideal gas, $$\Delta Q \neq \Delta W$$
D. Product of intensive and extensive variables is extensive
E. The ratio of any extensive variable to mass will be an extensive variable
Choose the correct combination of statements from the options given below:

A. Zeroth law gives concept of temperature
correct. it states that if two systems are each in thermal equilibrium with a third system, they are in equilibrium with each other. this allows us to define a common property called temperature.

B. First law gives concept of internal energy
correct. the first law relates heat, work and internal energy through ΔU = Q − W. this establishes internal energy as a state function of the system.

C. In isothermal expansion of ideal gas, ΔQ ≠ ΔW
wrong. in isothermal process, temperature remains constant so ΔU = 0. hence heat supplied is exactly equal to work done, so ΔQ = ΔW.

D. Product of intensive and extensive variables is extensive
correct. an intensive quantity does not depend on system size, while an extensive one does. multiplying them (like pressure × volume) gives a quantity that scales with size, so it is extensive.

E. Ratio of any extensive variable to mass is extensive
wrong. dividing an extensive quantity by mass gives a “specific” property (like density or specific heat), which does not depend on size, so it is intensive.