The correct response is: European colonizers’ cruelty, as well as the spread of disease, meant that many Indigenous people died. As a result, there were not enough people left for colonizers to enslave.
This is because the European colonizers subjected Indigenous peoples to brutal treatment and forced labor, leading to high mortality rates. Additionally, the introduction of diseases, such as smallpox, by the colonizers resulted in devastating epidemics among the Indigenous populations, further decreasing their numbers. Therefore, the combination of cruelty and disease significantly reduced the available pool of Indigenous people for enslavement, making it largely unsuccessful in filling the labor needs of the plantations.