A selected "[Serf]" belongs to a "[King]" which cannot be added to an Option--it was not added to the Option Set.
Namespace: Autodesk.Revit.DB
Assembly: RevitAPI (in RevitAPI.dll) Version: 26.1.0.0 (26.1.0.34)
Syntax
C#
public static FailureDefinitionId KingNeverInOption { get; }