Answer:
a. their temperatures
Step-by-step explanation:
Hello.
In this case, among the options:
a. their temperatures .
b. their internal energy contents .
c. their pressures .
d. whether they are in the solid, liquid, or gaseous state.
We must remember that the driving force assisting heat transfer is the temperature difference which states that the heat flows from higher temperatures to lower temperatures based on the second law of thermodynamics. Therefore answer is a. their temperatures .
Best regards.