Which microorganism is responsible for the production of citric acid in the tricarboxylic acid (TCA) cycle?
A. Citrobacter freundii
B. Saccharomyces cerevisiae (brewer's yeast)
C. Aspergillus niger
D. Escherichia coli (E. coli)
Citric acid is produced in the tricarboxylic acid (TCA) cycle, and Aspergillus niger is used in its production.