A drone flies in a straight line with a positive velocity v(t), in miles per hour, at time t hours, where v is a differentiable function of t. Selected values of v(t) are shown in the table. t(hours) 0 1 2 3 4 5 6
v(t)(miles per hour) 2.1 2.5 2.1 1.7 1.5 1.5 1.6
Based on the values in the table, what is the smallest number of instances at which the acceleration of the plane could equal zero on the open interval 0 c

0

1

2

3