Correct choice is (d) Stirred tank bioreactors
To elaborate: The bench-top bioreactor is a mechanically stirred tank bioreactor fitted with a sparger and a rushton turbine. And its volume varies from < 1-L to 10,000-L capacity. The air is added to the culture medium under pressure through a device called sparger. The sparger may be a ring with many holes or a tube with a single orifice. The sparger along with impellers (agitators) enables better gas distribution system throughout the vessel.
