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:
| Calls | Frequency | Branding | Format | Timeslot | Group owner |
| --- | --- | --- | --- | --- | --- |
| WGAN | 560 kHz | News Radio 560 WGAN | News/Talk | Live 3P-6P | Saga Communications |
| WHYN | 560 kHz | News/Talk 560 WHYN | News/Talk | Live 3P-7P | Clear Channel Communications |
| WVMT | 620 kHz | News/Talk 620 WVMT | News/Talk | Live 3P-7P | Sison Broadcasting |
| WRKO | 680 kHz | AM 680 WRKO | News/Talk | Live 3P-7P | Entercom |
| WCRN | 830 kHz | WCRN 830 True Talk | News/Talk | Live 3P-7P | Carter Broadcasting |
| WKBK | 1290 kHz | 1290 WKBK W281AU 104.1 | News/Talk | Live 3P-6P | Saga Communications |
| WEGP | 1390 kHz | WEGP 1390AM - The Talk of the County | News/Talk | Live 3P-6P | Decelles/Media, Inc. |
| WXTK | 95.1 MHz | News Radio 95 WXTK | News/Talk | Live 3P-7P | Qantam of Cape Cod, LLC |
| WNTK-FM | 99.7 MHz | WNTK Talk Radio | News/Talk | Live 3P-6P | Koor Communications |
| WUVR | 1490 kHz | WNTK Talk Radio | News/Talk | Live 3P-6P | Koor Communications |
| WVOM-FM / WVQM | 103.9/101.3 MHz | The Voice of Maine | News/Talk | Live 3P-7P | Blueberry Broadcasting |
Question:
Tell me the branding for frequency of 680 khz
Answer:
AM 680 WRKO