The Mississippi River which is over 2300 miles long is the second-longest river in the United States.

A、TheMississippiRiverwhichisover2300mileslongisthesecond-longestriverintheUnitedStates.(Nocommas);
B、TheMississippiRiver,whichisover2300mileslongisthesecond-longestriverintheUnitedStates.;
C、TheMississippiRiverwhichisover2300mileslong,isthesecond-longestriverintheUnitedStates.;
D、TheMississippiRiver,whichisover2300mileslong,isthesecond-longestriverintheUnitedStates.