A revolving rifle fires 9mm bullets. As the bullets travel down the barrel of the rifle, their speed is given by the equation v=(-4.90×10^7)t2+(2.20×10^5)t, where v is in meters per second and t represents time. Which of the following best represents the equation for the speed of the bullets?

A) v = -4.90×10^7t2 + 2.20×10^5t
B) v = -4.90×10^7t2 + 2.20×10^5t + 9mm
C) v = -4.90×10^7t2 + 2.20×10^5t - 9mm
D) v = -4.90×10^7t2 + 2.20×10^5t + 9m/s