Slavery arose in the southern colonies partly as a perceived economical way to:

The choice highlighting the cultivation of large plantations of cotton, tobacco, rice, indigo, and other crops is correct because it directly addresses the economic motivations behind the establishment of slavery in the southern colonies. The geographical and climatic conditions of the South were well-suited for the intensive farming of these cash crops, which required a significant labor force to be economically viable.

Landowners sought to maximize their profits and expand their agricultural output by using enslaved Africans as a reliable source of labor. This demand for labor led to the growth of the plantation system, which was heavily dependent on enslaved individuals who worked the land under harsh conditions. As these crops became increasingly profitable in European markets, the reliance on slavery deepened, further embedding the institution in the economic framework of the southern colonies.

The other choices do touch on relevant topics but do not fully capture the central economic reasons for the rise of slavery. For instance, while wealth accumulation through human labor is a component of the discussion, it lacks the specific context of agricultural production. Humanitarian aid and cargo transport also divert from the fundamental economic motivations that drove the demand for slave labor in agriculture.