Survey questions can be made optional and mandatory in Survey Definition.
Details
Go to Manage Surveys under Manage Portfolio as shown below:
Expand the survey you need to make changes to and then click on the star icon to change the question type as optional or mandatory. "grey star" mean optional, "yellow star" mean mandatory.
Additional Resources
CAST Highlight Troubleshooting Guides
CAST Highlight Product Documentation
Zendesk Ticket Number
23876
Comments