What percentage of serious historians say the civil war was fought over slavery

Plz which of the following statements about the fugitive slave act of 1850 is not accurate? a. marshals you refuse to arrest a suspected fugitive could be find $1000. b. slave owners had to present evidence 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 of federal marshals to arrest any african-american suspected of being a runaway slave.