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:
| Location | Venue | Promotion | Event | Inductee(s) |
| --- | --- | --- | --- | --- |
| Philadelphia, Pennsylvania | ECW Arena | Pro-Pain Pro Wrestling | A Night for the Flyboy | Rocco Rock |
| Philadelphia, Pennsylvania | Alhambra Arena | Hardcore Homecoming | November Reign | Terry Funk |
| Philadelphia, Pennsylvania | Alhambra Arena | Pro Wrestling Unplugged | The Crazy 8 | Johnny Grunge , The Sandman |
| Philadelphia, Pennsylvania | Alhambra Arena | Combat Zone Wrestling | Cage of Death X | John Zandig |
| Philadelphia, Pennsylvania | The Arena | Legends of the Arena | Legends of the Arena | Eddie Gilbert , Chris Candido , Tod Gordon , Sabu |
| Philadelphia, Pennsylvania | The Arena | Combat Zone Wrestling | Acid-Fest | Trent Acid |
| Philadelphia, Pennsylvania | The Arena | Ring of Honor | Ring of Honor Wrestling | Jerry Lynn |
| Philadelphia, Pennsylvania | The Arena | Chikara | Chikarasaurus Rex: King of Show | Tommy Dreamer |
Question:
What is the promotion when the event was Acid-fest?
Answer:
Combat Zone Wrestling