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:
| No. in series | No. in season | Title | Directed by | Written By | Originalairdate | TV Broadcast |
| --- | --- | --- | --- | --- | --- | --- |
| 117.0 | 1.0 | "Future Shellshock" | Roy Burdine | Marty Isenberg | July29,2006 | S06E01 |
| 118.0 | 2.0 | "Obsolete" | Roy Burdine | Adam Beechen | August5,2006 | S06E02 |
| 119.0 | 3.0 | "Home Invasion" | Roy Burdine | Rich Fogel | August12,2006 | S06E03 |
| 120.0 | 4.0 | "Headlock Prime" | Roy Burdine | Steven Melching | September30,2006 | S06E04 |
| 121.0 | 5.0 | "Playtime's Over" | Roy Burdine | Julia Lewald | October7,2006 | S06E05 |
| 122.0 | 6.0 | "Bishop to Knight" | Roy Burdine | Steve Murphy | October14,2006 | S06E06 |
| 123.0 | 7.0 | "Night of Sh'Okanabo" | Roy Burdine | Michael Ryan | October21,2006 | S06E07 |
| 124.0 | 8.0 | "Clash of the Turtle Titans" | Roy Burdine | Marty Isenberg | October28,2006 | S06E08 |
| 125.0 | 9.0 | "Fly Me to the Moon" | Roy Burdine | Rich Fogel | November4,2006 | S06E09 |
| 126.0 | 10.0 | "Invasion of the Bodyjacker!" | Roy Burdine | Roger Slifer | November11,2006 | S06E10 |
| 127.0 | 11.0 | "The Freaks Come Out at Night" | Roy Burdine | Marty Isenberg | November25,2006 | S06E11 |
| 128.0 | 12.0 | "Bad Blood" | Roy Burdine | Roland Gonzalez | December2,2006 | S06E12 |
| 129.0 | 13.0 | "The Journal" | Roy Burdine | Steve Murphy | December9,2006 | S06E13 |
| 130.0 | 14.0 | "The Gaminator" | Roy Burdine | Wendell Morris | December16,2006 | S06E14 |
| 131.0 | 15.0 | "Graduation Day: Class of 2105" | Roy Burdine | Julia Lewald | March24,2007 | S06E15 |
| 132.0 | 16.0 | "Timing Is Everything" | Roy Burdine | Joe Kelly | March31,2007 | S06E16 |
| 133.0 | 17.0 | "Enter the Jammerhead" | Roy Burdine | Julia Lewald | April7,2007 | S06E17 |
| 134.0 | 18.0 | "Milk Run" | Roy Burdine | Steven Melching | April14,2007 | S06E18 |
| 135.0 | 19.0 | "The Fall of Darius Dunn" | Roy Burdine | Rich Fogel | April21,2007 | S06E19 |
| 136.0 | 20.0 | "Turtle X-Tinction" | Roy Burdine | Marty Isenberg | April28,2007 | S06E20 |
| 137.0 | 21.0 | "Race For Glory" | Roy Burdine | Larry Hama | September8,2007 | S06E21 |
| 138.0 | 22.0 | "Head of State" | Roy Burdine | John Drdek | September15,2007 | S06E22 |
| 139.0 | 23.0 | "DNA is Thicker than Water" | Roy Burdine | Roland Gonzalez | October6,2007 | S06E23 |
| 140.0 | 24.0 | "The Cosmic Completist" | Roy Burdine | James Felder | October13,2007 | S06E24 |
| 141.0 | 25.0 | "The Day of Awakening" | Roy Burdine | Steve Murphy | October20,2007 | S06E25 |
Question:
Who was the director of the episode "graduation day: class of 2105"?
Answer:
Roy Burdine