Question

what gave rise to the slave trade?
the lack of a skilled labor force in the americas and the decline of the west african population caused residents to seek a living elsewhere.
the shipment of gold from the americas to europe caused plantation owners to seek inexpensive laborers.
the death of many indigenous peoples to disease and the planting of labor - intensive crops.
the global expansion of the spice trade and the rise of christianity in the americas.

Explanation:

The death of many Indigenous peoples due to diseases led to a labor - shortage in the Americas. Planting labor - intensive crops required a large amount of labor, which gave rise to the slave trade. The first option has wrong reasons as the decline of West African population didn't cause slave trade and lack of skilled labor is not the main cause. The second option about gold shipment is not the root cause. The fourth option about spice trade and rise of Christianity has no direct relation to the emergence of slave trade.

Answer:

The death of many Indigenous peoples to disease and the planting of labor - intensive crops.