Penicillin is made in a fermenter by cultivating the fungus Penicillium. The graph illustrates how the mass of living Penicillium fungus and the concentration of penicillin vary with time. At what point is it best to harvest the penicillin?
- Aat 1.5 days
- Bat 3.0 days
- Cat 3.5 days
- Dat 5.0 days