CSTR reactor (220 m³) uses ozone as primary disinfectant which treats 50,000 m³/day of drinking water. The ozone is bubbled into the water as it passes through the tank to reach 90% of Giardia (bacteria) reduction efficiency. If the Giardia reaction rate constant is given as K=kc Coz wher Coz is the ozone concentration and ke=3000 L/mg.day, what should be the minimum ozone concentration that should be used to achieve the required removal of Giardia? O a. 2.83 mg/L Ob. 5.73 mg/L O c. 6.4 mg/L O d. 0.68 mg/L O e. 1.1 mg/L