The correct option is A Bioreactor
Large scale production of enzymes for commercial purposes requires bioreactors which can accommodate large volumes (100-1000 litres) of culture.
Microbial, plant or animal cells are added to these cylindrical vessels along with raw materials at optimal growth conditions (temperature, pH, vitamins, oxygen, etc.) to convert into specific products (enzymes).
BOD incubator (Biological oxygen demand incubator) is widely used in microbiology laboratories. It is generally designed with a temperature range between 5°C to 60°C. It has both cooling and heating functions under one unit.
In sludge digesters, the anaerobic microbes break down organic materials into methane and carbon dioxide.
Industrial ovens are used for a variety of industrial applications, including drying, curing, or baking.