| 1 | A | B | C | D |
| --- | --- | --- | --- | --- |
| 2 | Adaptive Multi-Rate audio codec - Usage |  |  |  |
| 3 | Mode | Bitrate (kbit/s) | Channel | Compatible with |
| 4 | AMR_12.20 | 12.20 | FR | ETSI GSM enhanced full rate |
| 5 | AMR_10.20 | 10.20 | FR | - |
| 6 | AMR_7.95 | 7.95 | FR/HR | - |
| 7 | AMR_7.40 | 7.40 | FR/HR | TIA/EIA IS-641 TDMA enhanced full rate |
| 8 | AMR_6.70 | 6.70 | FR/HR | ARIB 6.7 kbit/s enhanced full rate |
| 9 | AMR_5.90 | 5.90 | FR/HR | - |
| 10 | AMR_5.15 | 5.15 | FR/HR | - |
| 11 | AMR_4.75 | 4.75 | FR/HR | - |
| 12 | AMR_SID | 1.80 | FR/HR | - |

Question: What bitrates do the AMR codecs use?
Answer: The AMR codec uses eight codecs with bit-rates of 12.2, 10.2, 7.95, 7.40, 6.70, 5.90, 5.15 and 4.75 kbit/s.