On the extension of side $BC$ of the triangle $ABC$ consider the point D such that $C$ is between $B$ and $D$ and $AC = CD.$ Let M be an arbitrary point on the angle bisector of $\angle ACD$. Prove that $MA + MB > CA + CB.$ [![enter image description here](https://i.stack.imgur.com/4OV7V.png)](https://i.stack.imgur.com/4OV7V.png)

I am completely stuck on this question. I don't know how to approach it. Any help would be greatly appreciated.