The question itself is an implicit test of logical deduction to determine the most likely assumptions given the restraints imposed by the question. Just becaus

The question itself is an implicit test of logical deduction to determine the most likely assumptions given the restraints imposed by the question. Just because random things are possible (the husband had two wives!), does not make them the most likely assumptions given the nature of the question. If the answer was "Unrelated - Jane's dad had a harem of several women", the question wouldn't make much sense on any type of quiz designed to determine intelligence.