An object's position in meters and motion in meters per second can be described by 2=−18−3t+t² during the time interval 0≤t≤2. What statements is the best description of the object's motion?
A. The acceleration of the object is zero
B. The initial position of the object is -18 meters
C. The object's speed is decreasing
D. The average velocity of the object is -3 m/s