How do we default a value in Select Single whose data is coming from REST endpoint ?

Summary:

We have one drop down (Select Single) in our page whose data is coming from a remote REST call. Once we select the dropdown then the data is getting loaded. We have a requirement to select a default value in the Select Single.

For example -

We are designing a payroll interface. Where we are searching for a person in Person Search page, then once a person is selected from the search result, we are navigating to a details page for the person. In the details page there is a drop down of Payroll Relationships. A person can have multiple Payroll Relationships, out of which one is default. So we need to default the Single Select with default Payroll Relationship.