The correct option is A Stirring type
Bioreactors are large cylindrical vessels that are used for large scale culturing of cells (plant, animal or microbial cells) to obtain specific gene products for commercial use.
A stirred-tank bioreactor has a cylindrical shape and curved base which facilitates the even mixing of all the contents in the culture. The stirrer helps in uniform mixing and distributes oxygen uniformly throughout the bioreactor. It can be used for large scale production.
A simple bioreactor has an agitator system, an oxygen delivery system, a foam control system, temperature and pH control system, sampling ports, cleaning, and sterilization system.
Hence the correct option is
b. Stirring type