Final answer:
The height of the Atlantic slave trade, dominated by Spanish merchants and ships, occurred in the eighteenth century.
Step-by-step explanation:
The correct answer is Option 1: The eighteenth century. During the eighteenth century, the Atlantic slave trade reached its peak, with the Spanish playing a vital role in the commerce. Spanish merchants and ships dominated the transatlantic slave trade, transporting millions of enslaved Africans to the Americas.
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