An equation of a function y(t) is shown. y(t)=−t²+14t−40 which of the following statements are true about the graph of y(t) for 6≤t≤8 and why? a. the value of y(t) increases over the interval 6≤t≤7 b. the value of y(t) increases over the interval 7≤t≤8 c. the average rate of change over the interval 6≤t≤8 is 0 d. the value of y(t) is constant over the interval 6≤t≤8 e. the average rate of changer over the interval 6≤t≤7 is the same as the average rate of change over the interval 7≤t≤8