Selected Option is part of a Switch Actor property. When attempted to add the property in variant manager, the property named selected option doesn't show up in variant manager properties.
Reported in version 4.25.3(CL 13942748). Tested with same result in versions 4.25.3 and 4.24.3(CL 11590370).
Results: The selected option property is not available in the variant manager.
Expected: The selected option property should be available as an option in the variant manager properties panel.
There's no existing public thread on this issue, so head over to Questions & Answers just mention UE-100346 in the post.