In Castor SMS, each multiple choice field has an option group with different options. It is possible to add a new option or edit an existing option in an option group.

Follow the steps below to add or edit an option in an option group:

1. To edit an option group, first navigate to 'Settings' > 'Configurations' and click on the 'Option groups' tab.
2. Here you see all option groups in the system. Use the search bar to find one you would like to update. Each option has a value, a name in English, and a name in Dutch. The value is used to identify the option in the backend. The name is what you see as your option in the system.
3. When you find the option you want to change, use the menu on the right and choose ‘edit’. You can now update the option. Click 'Save' to save the changes.
4. To add an option to the option group, click on the 'Add' button. Because Castor SMS can be shown in Dutch and English, you’ll need to add the names in both languages. You will also need to pick a value, make sure that the value you choose is unique within the option group.
5. Click on the 'Save' button to add a new option.
6. Refresh the browser window to see the new changes. Navigate to the 'Studies' tab and open any study to view the changes in the study.