A fed-batch reactor containing 2 litre of medium and 0.1 g.l-l of biomass is fed with a medium containing 1 g.l-1 of substrate at 1 litre per hour. If after 10 hours, the concentration of biomass in the reactor was 0.2 g.l-1, then the biomass produce

• A. 2.2 g
• B. 1.5 g
• C. 6.0 g
• D. 3.0 g