Use the definition to find an expression for the instantaneous acceleration of an object moving with rectilinear motion according to the given function. The instantaneous acceleration is defined as the instantaneous rate of change of the velocity with respect to time. The displacement (s) as a function of time (t) is given below. Find the velocity as a function of t, and then find the acceleration. s = 819 - 21- + 8 O A. 32t - 4 O B. 48t - 4 O C. 4t- 32 O D. 4t - 48