A bobsled has a momentum of 4000 0 kg* m/s to the south. Friction on the track reduces its momentum to 500 kg* m/s to the south. What impulse is applied to the bobsled by the friction?

A. 6500 kg* m/s north

OB. 1500 kg* m/s south O

C. 6500 kg* m/s south

O 1500 kg* m/s north