Which nation began the practice of brining humans from Africa for sale in the Americas?

The Portuguese, in the 16th century, were the first to engage in the Atlantic slave trade. In 1526, they completed the first transatlantic slave voyage to Brazil, and other Europeans soon followed.

Explanation:

The Portuguese were the first ones that practiced slavery. They were followed by the English, Spanish, and French.

the anwser is a) to prevent military conflict