An automobile is driven on a straight road, and the distance traveled by the automobile after time t=0 is given by a quadratic function a where a(t) is measured in feet and t is measured in seconds for 0 <= t <= 12. Of the following, which gives the best estimate of the velocity of the automobile, in feet per second, at time t = 8 seconds? a. s(8)
b. s(8)/8
c. s(12)- s(2)/ 12-2
d. s(9)- s(7)/9-7