Which sentence from the article is the best evidence that the cotton gin could have led to an increase of slavery?

a. At first, people separated cotton seeds by hand. It took a long time, so cotton farmers didn’t make a lot of money.,

b. Cotton plantation owners planted more and more cotton, so they brought many more enslaved people to the South to help tend their larger cotton crops.,

c. The cotton gin could clean more cotton in a few minutes that a whole team of workers could clean by hand in a day.,

d. The cotton gin quickly separated the seeds from the cotton fiber.