Which of the following is NOT supported by Flow Designer?

Which of the following is NOT supported by Flow Designer?

A. Call a subflow from a flow

B. Test a flow with rollback

C. Use Delegated Developer
D. Run a flow from a MetricBase Trigger

Reference: https://community.servicenow.com/community?id=community_question&sys_id=b4d26e44db13ab409540e15b8a9619c9