“Membrane Bioreactors” are often discussed in the context of:

Wastewater treatment technologies

Membrane Bioreactors (MBRs) combine biological wastewater treatment with membrane filtration. Microorganisms break down organic pollutants, while membranes separate treated water from suspended solids and biomass. They are widely used in municipal and industrial wastewater treatment. Option A is incorrect because assisted reproductive technologies concern fertility and reproduction. Option B refers to drug-delivery systems, not MBRs. Option C concerns vaccine development and production. Therefore, option D is correct.