Can you please explain which answer is correct. Thanks

Which of the following is true? a. Irreducible Markov chains with one communicating class must be positive recurrent. ) b. Irreducible Markov chains always have an equilibrium state, but they may not have a limiting distribution. ) c. Infinite state irreducible Markov chains can have several communicating classes. _) d. Ifthe expected return time to a state of a Markov chain is finite, then the Markov chain is positive recurrent. _. e. There are transient, irreducible Markov chains