How can I demostrate that language $\displaystyle \Gamma$ have words of any large exept two?

$\displaystyle (i) \epsilon\in\Gamma$

$\displaystyle (ii)a\in\Gamma$

$\displaystyle (iii)\mbox{ If } \alpha\in\Gamma\mbox{ and }\beta\in\Gamma, \Rightarrow b\alpha c\beta b \in\Gamma$

Thank you!