Starting at time t = 0 s, a motorboat travels at a constant velocity of 12 m/s for 10 s. The motorboat then changes
speed over the next 5 s. At a time of t = 15 s, It reaches a speed of 18 m/s and travels at that speed for 45 s. Which
of the following must be true about the motorboat's motion?
O A. The instantaneous velocity at t = 61 s is 18 m/s.
B. The instantaneous velocity at t = 12.5 s is 15 m/s.
OC. The average velocity over the first 10 s is the same as the instantaneous velocity.
D. none of the above