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:
| Standard Yarn Weight System | Yarn Type (US) | Ply (UK, NZ, AU) | m/100g | Wraps Per Inch (WPI) |
| --- | --- | --- | --- | --- |
| 0 or Lace | Thread, Cobweb and Lace | 1 - 3 ply | 600-800 | 18+ wpi |
| 1 or Superfine | Fingering | 4 ply | 400-480 | 14 wpi |
| 2 or Fine | Sport | 5 ply | 300-400 | 12 wpi |
| 3 or Light | DK | 8 ply | 240-300 | 11 wpi |
| 4 or Medium | Worsted | 10 ply | 120-240 | 9 wpi |
| 5 or Bulky | Bulky | 12 ply | 100-130 | 7 wpi |
Question:
Name the standard yarn weight system for 9 wpi
Answer:
4 or Medium