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:
| Model | Floating point | Decimal | Byte string | Memory map | Max memory (kwords) |
| --- | --- | --- | --- | --- | --- |
| Sigma 7 | optional | optional | standard | optional | 128.0 |
| Sigma 5 | optional | N/A | N/A | N/A | 128.0 |
| Sigma 6 | optional | standard | standard | standard | 128.0 |
| Sigma 9 | standard | standard | standard | standard | 512.0 |
| Sigma 8 | standard | N/A | N/A | N/A | 128.0 |
| Sigma 9 model 2 | standard | standard | standard | standard | 256.0 |
| Sigma 9 model 3 | standard | N/A | N/A | standard | 512.0 |
Question:
When a Sigma 7 has a standard byte string, what is the value for the decimal?
Answer:
optional