Two weakly coupled Einstein solids, A and B, each containing 6 oscillators, share a total of 12 units of energy. a. How many different macrostates are available to this system? b. How many different microstates are available to this system? c. Assuming that this system is in thermal equilibrium, what is the probability of finding half the energy in solid A? d. What is the most probable macrostate and its probability? e. Under what circumstances would this system exhibit irreversible behavior?