Bacterium A. Aspergillus niger B. Acetobacter acetic C. Clostridium bretylium D. Lactobacillus | Product i. Lactic acid ii. Butyric acid iii. Acetic acid iv. Citric acid |
Aspergillus niger is commercially used for the production of citric acid.
Acetobacter acetic is commercially used for the production of acetic acid.
Clostridium bretylium is commercially used for the production of butyric acid.
Lactobacillus is commercially used for the produce of lactic acid.
So, the correct answer is (c).