2. (2.5 points) The figure below shows a plot of BOD remaining versus time for a sample of effluent taken from a wastewater treatment plant. BOD remaining (mg/L) 40 35 30 25 20 15 10 5 W 0 0 12 3 4 5 6 7 8 9 10 11 Days (a) What is the ultimate BOD (Lo)? (0.5 point) (b) What is Ls? (0.5 point) (c) What is the five-day BOD (BODs)? (0.5 point) (d) If BOD decays in first order, estimate the reaction rate constant k (in day¹). (1 point)