the function d defined above models the depth, in feet, of the water t hours after 12 a.m. in a certain harbor. which of the following presents the method for finding the instantaneous rate of change of the depth of the water, in feet per hour, at 6 a.m. ?D(6)-DO/6-0 = -1.633 B D(6) = 0 С D" (6) = 1.343 D(6) = 5.100