The Option Set will not be visible when you select in function bar but you can view it in a label by writing the option set name.
e.g. If your option set is Status and its values are Pending, Approved, Rejected.
you can view it in label by writing the below function -
For Showing Pending : Label's Text Property = Status.Pending
For Showing Approved : Label's Text Property = Status.Approved
For Showing Rejected : Label's Text Property = Status.Rejected
Please accept my answer as Accept as Solution if it solves your query.
Thanks
Dipak Shaw