Two football players are running toward each other. One football player has a mass of 105 kg and is running at 8.6 m/s. The other player has a mass of 90 kg and is running at -9.0 m/s.
What is the momentum of the system after the football players collide?
A. 93 kg · m/s
B. 1,713 kg · m/s.
C. 810 kg · m/s.
D. 903 kg · m/s.