Question 3 (1 point) Saved Let the function M(t) denote the mass of bacteria culture (in mg) at time t days. The average rate of change of M(t) is 1.4 mg/day over the time interval [2, 7] and is 0.6 mg/day over the time interval [4, 7]. The average rate of change of M(t) over the time interval [2, 4] is 52 mg / day $7 mg / day be mg / day 4. 7 mg / day 5. 1 mg / day None of the above