The displacement of a particle is shown in the plot. Which of the following statements concerning this plot is not correct?
a. At t1, the instantaneous velocity is less than the instantaneous velocity at t4.
b. The instantaneous velocities of t2 and t4 are significantly different.
c. The instantaneous velocities at t3 and t5 are significantly different.
d. The only labeled points for which instantaneous velocity is negative are t2 and t6.