• repealed the Missouri Compromise of 1820
  
• was created as a means of constructing a transcontinental railroad
  
• created two new states in the middle of the United States
  
• let the states decide whether or not to allow slavery
  
  

Which law is being described here?

AGadsden Purchase

BNorthwest Ordinance

CKansas-Nebraska Act of 1854

DOregon-Washington Purchase of 1848