The correct option is D Bioreactor
Bioreactors are large vessels which are used for the large-scale culturing of host cells (microbial cells, plant cells or animal cells) containing recombinant DNA to obtain the bioengineered products. In the bioreactors, raw materials are converted into specific products like proteins.
Depending on the type of bioreactor used, provisions for aeration, agitation, overflow vents, sampling ports, temperature and pH control systems, etc. are provided.
PCR or polymerase chain reaction is a process by which DNA amplification is done for a desired sequence of DNA.
Agitators are apparatus which help in stirring and mixing of liquids.
An incubator is an apparatus which provides optimum conditions for growing and maintaining microbial or cell cultures at a smaller scale, usually in laboratories.