I have just come back from Tiawam ,the biggest of China.改为定语从句?

问题描述:

I have just come back from Tiawam ,the biggest of China.改为定语从句?

I have just come back from * which is the biggest island of China.
题目不全,不过我估计是这样的。

I have just come back from * which is the biggest island of China.

I have just come back from Tiawam ,which is the biggest of China.

I have just come back from Tiawam ,which is the biggest of China.