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 | U.S. air date | Production code | U.S. viewers (million) |
| --- | --- | --- | --- | --- | --- | --- | --- |
| 154.0 | 2.0 | "Plastique" | Rick Rosenthal | Don Whitehead & Holly Henderson | September25,2008 | 3T7452 | 4.18 |
| 155.0 | 3.0 | "Toxic" | Mairzee Almas | Caroline Dries | October2,2008 | 3T7453 | 4.05 |
| 156.0 | 4.0 | "Instinct" | James Conway | Al Septien & Turi Meyer | October9,2008 | 3T7454 | 4.11 |
| 157.0 | 5.0 | "Committed" | Glen Winter | Bryan Q. Miller | October16,2008 | 3T7455 | 4.18 |
| 158.0 | 6.0 | "Prey" | Michael Rohl | Kelly Souders & Brian Peterson | October23,2008 | 377456 | 4.15 |
| 159.0 | 7.0 | "Identity" | Mairzee Almas | Todd Slavkin & Darren Swimmer | October30,2008 | 3T7457 | 4.32 |
| 160.0 | 8.0 | "Bloodline" | Michael Rohl | Caroline Dries | November6,2008 | 3T7459 | 4.45 |
| 161.0 | 9.0 | "Abyss" | Kevin G. Fair | Don Whitehead & Holly Henderson | November13,2008 | 3T7458 | 3.55 |
| 162.0 | 10.0 | "Bride" | Jeannot Szwarc | Al Septien & Turi Meyer | November20,2008 | 3T7460 | 4.18 |
| 163.0 | 11.0 | "Legion" | Glen Winter | Geoff Johns | January15,2009 | 3T7461 | 4.29 |
| 164.0 | 12.0 | "Bulletproof" | Morgan Beggs | Bryan Miller | January22,2009 | 3T7462 | 3.85 |
| 165.0 | 13.0 | "Power" | Allison Mack | Todd Slavkin & Darren Swimmer | January29,2009 | 3T7463 | 4.21 |
| 166.0 | 14.0 | "Requiem" | Michael Rohl | Don Whitehead & Holly Henderson | February5,2009 | 3T7464 | 3.93 |
| 167.0 | 15.0 | "Infamous" | Glen Winter | Caroline Dries | March12,2009 | 3T7465 | 3.56 |
| 168.0 | 16.0 | "Turbulence" | Kevin G. Fair | Al Septien & Turi Meyer | March19,2009 | 3T7466 | 3.49 |
| 169.0 | 17.0 | "Hex" | Mairzee Almas | Bryan Miller | March26,2009 | 3T7467 | 3.79 |
| 170.0 | 18.0 | "Eternal" | James Marshall | Brian Peterson & Kelly Souders | April2,2009 | 3T7468 | 3.84 |
| 171.0 | 19.0 | "Stiletto" | Kevin G. Fair | Caroline Dries | April23,2009 | 3T7469 | 3.10 |
| 172.0 | 20.0 | "Beast" | Michael Rohl | Genevieve Sparling | April30,2009 | 3T7470 | 3.23 |
| 173.0 | 21.0 | " Injustice" | Tom Welling | Al Septien & Turi Meyer | May7,2009 | 3T7471 | 3.39 |
Question:
When there are  3.39 million u.s viewers what is the production code?
Answer:
3T7471