Please read the following table in Markdown format and then answer the question according to the table. Table cells in one row are seperated by '|', and different rows are seperated by '
'.

Table:
| State | Type | Name | Title | Royal house |
| --- | --- | --- | --- | --- |
| Cai | Sovereign | Wu | Marquis | Ji |
| Cao | Sovereign | Yi | Count | — |
| Chen | Sovereign | You | Duke | — |
| Jin | Sovereign | Li | Marquis | Ji |
| Jin | Sovereign | Jing | Marquis | Ji |
| Lu | Sovereign | Xian | Duke | Ji |
| Lu | Sovereign | Shen | Duke | Ji |
| Qi | Sovereign | Xian | Duke | Jiang |
| Qi | Sovereign | Wu | Duke | Jiang |
| Qin | Sovereign | Feizi | Ruler | Ying |
| Qin | Sovereign | Marquis | Ruler | Ying |
| Song | Sovereign | Li | Duke | — |
| Wey | Sovereign | Qing | Marquis | — |
| Wey | Sovereign | Li | Marquis | — |
| Yan | Sovereign | Hui | Marquis | — |
Question:
What is the royal house for Wu at the state of cai?
Answer:
Ji