What is the central idea of the underground railroad?

Which of the following statements about the fugitive slave act of 1850 is not accurate. a. marshals who refused to arrest a suspected fugitive could be fined $1,000. b. slave owners had to present evidence that an african american in the north was a fugitive slave. c. any person who provided food or shelter to a fugitive slave could be find $1000 and placed in jail for six months. d. it required all federal marshals to arrest any african-american suspected of being a runaway slave.