A Particle Is Moving at Constant Velocity

Multiple Choice

A particle is moving at constant velocity. Its position at t = 1.0 s is 3.0 m and its position at t = 4.0 s is 15.0 m. What is the slope of the position-time graph for this particle?

A) 0, since this is a constant velocity situation.
B) 4.0 m/s
C) 4.0 m/s2
D) 9.0 m/s
E) 12 m/s2