Markov Chain probabilities

A Markov chain on state space {1,2,3,4,5} has transition matrix

$\displaystyle

\begin{pmatrix}

0 & 0 & 1 & 0 & 0\\

0 & 0 & 4/{5} & 1/{5} & 0\\

0 & 1/{6} & 2/{3} & 0 & 1/{6}\\

0 & 0 & 0 & 1 & 0\\

0 & 0 & 0 & 0 &1\\

\end{pmatrix}

$

The process starts in state 1.

a) Which states are absorbing?

b) Calculate the probability that the process is absorbed at state 4 (ends up at state 4).

c) Calculate the expectation of the time of absorption.

I am missed my lectures due illnes so I don't have much understanding of this topic. I would be grateful for some help with this revision question.

Thanks