The classification turns on a definite question: are children present, and if so, are they daughters, sons, or both?
ConditionCategory
Children: daughters onlyināthan
Children: sons onlyal-dhukūr
Children: bothdhukrānan wa-ināthan
No childrenʿaqīman
If the first three cases were mentioned without childlessness, the classification would not be exhaustive. The rhetorical distinction is therefore completeness relative to a specific criterion, not merely having several labels.