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:
| Res. | Record | Opponent | Method | Event | Round | Time |
| --- | --- | --- | --- | --- | --- | --- |
| Win | 8-0 | Mychal Clark | Decision (unanimous) | Call to Arms: Called Out Fights | 3.0 | 5:00 |
| Win | 7-0 | Jeff Ford | TKO (shoulder injury) | Call to Arms I | 1.0 | 1:23 |
| Win | 6-0 | Richard Dalton | Decision (unanimous) | Strikeforce: Playboy Mansion | 3.0 | 5:00 |
| Win | 5-0 | Michael Alden | TKO (head kick & punches) | BodogFight Series III: Costa Rica Combat | 1.0 | 0:45 |
| Win | 4-0 | Mike Cook | Submission (rear naked choke) | Strikeforce: Triple Threat | 2.0 | 2:31 |
| Win | 3-0 | Tom Tuggle | Submission (armbar) | Strikeforce: Revenge | 1.0 | 0:28 |
| Win | 2-0 | Jesse Fujarczyk | Submission (rear naked choke) | Strikeforce: Shamrock vs. Gracie | 1.0 | 1:54 |
| Win | 1-0 | Jay McCown | Decision (unanimous) | X-1 | 3.0 | 3:00 |
Question:
Which Opponent has a Time of 2:31?
Answer:
Mike Cook