Final answer:
When a territory under the Northwest Ordinance of 1787 had 5,000 free adult male settlers, it could elect its own legislature, marking a step towards self-governance.
Step-by-step explanation:
The question pertains to the provisions of the Northwest Ordinance of 1787 regarding the governance of territories with a certain population of free settlers. The main answer is that when an area under the Northwest Ordinance of 1787 reached 5,000 free adult male settlers, it could elect a legislature (Option 4). Originally governed by a governor, secretary, and judges appointed by Congress, the population milestone allowed for increased self-governance within the territory.In depth, when the population in the territory reached five thousand free adult settlers, those citizens could create their own legislature and begin the process of moving toward statehood. However, the governor was still appointed by Congress until the population exceeded 60,000, at which point the territory could adopt a constitution and apply for statehood.Conclusion: Thus, for a territory with 5,000 free adult male settlers under the Northwest Ordinance, the correct option is that it could elect a legislature, taking a step towards self-governance while still under the oversight of a Congress-appointed governor until it reached a population suitable for statehood.