If you have access to both audio inputs and outputs in your Audio card driver on the Audio tab in Reason's Preferences - but still don't get any audio input in Reason - it could be a Privacy setting in macOS that has to be configured:
1. Open System Preferences.
2. Open the Security & Privacy settings.
3. Click the Privacy tab.
4. Select Microphone in the left column.
5. In the right column, make sure Reason 10/11/12 is enabled (checked box):