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. | # | Title | Directed by | Written by | Original air date | Production code | U.S. viewers (million) |
| --- | --- | --- | --- | --- | --- | --- | --- |
| 13.0 | 1.0 | "Red Rain" | Bryan Spicer | Scott Rosenbaum & Gregg Hurwitz | January4,2011 | 3X6201 | 6.59 |
| 14.0 | 2.0 | "Serpent's Tooth" | Steve Shill | Gregg Hurwitz | January11,2011 | 3X6202 | 5.77 |
| 15.0 | 3.0 | "Laid Bare" | David Barrett | Gwendolyn M. Parker | January18,2011 | 3X6203 | 5.70 |
| 16.0 | 4.0 | "Unholy Alliance" | Dean White | Rockne S. O'Bannon | February1,2011 | 3X6204 | 5.29 |
| 17.0 | 5.0 | "Concordia" | Jesse Warn | David Rambo | February8,2011 | 3X6205 | 5.40 |
| 18.0 | 6.0 | "Siege" | John Behring | Dean Widenmann | February15,2011 | 3X6206 | 5.43 |
| 19.0 | 7.0 | "Birth Pangs" | David Barrett | Cathryn Humphris | February22,2011 | 3X6207 | 5.14 |
| 20.0 | 8.0 | "Uneasy Lies the Head" | Jeff Woolnough | Cameron Litvack & Gregg Hurwitz | March1,2011 | 3X6208 | 5.04 |
| 21.0 | 9.0 | "Devil in a Blue Dress" | Ralph Hemecker | Hans Tobeason | March8,2011 | 3X6209 | 4.98 |
Question:
What is the production code of the episode written by Cathryn Humphris?
Answer:
3X6207