Answer:
Option: attacking pro slavery settlers.
Step-by-step explanation:
John Brown, in reply to the Fugitive Slave Act of 1850, decided to act against it. The act ordered runaway slaves to return to their owners, even if they entered in a free state. The act made the government accountable for returning, finding, and trying escaped slaves. Brown established a group to prevent the capture of escaped slaves from their masters. Brown also found proslavery supporters and hoped of making Kansas a free state, he went west to join the antislavery cause.