Who sells people into the slave trade

Which of the following would a historian most likely study to find data

According to the article,"social credit" is question 3 options: an experiment to people talk on-line a farming experiment that hurt people under mao ze dong using someone else's data from the internet, to give or take away things such as the right to buy an airline ticket a credit you get in china for having friends in real life, and not just on social media

What was the purpose of the cuban revolution