Identify the blank spaces A, B, C and D and select the correct option…

The correct answer is Option (1) → A- Lactobacillus
B- Trichoderma polysporum
C- Acetic acid
D- Penicillin

A — the bacterium that gives lactic acid is Lactobacillus. It belongs to the lactic acid bacteria (LAB), which also turn milk into curd.

B — cyclosporin A, used to suppress the immune system in organ-transplant patients, is made by the fungus Trichoderma polysporum. Aspergillus niger is a fungus too, but it is used for citric acid.

C — the bacterium Acetobacter aceti is used to make acetic acid. Citric acid comes from Aspergillus niger, and butyric acid from the bacterium Clostridium butylicum.

D — the fungus Penicillium notatum gives penicillin, the first antibiotic to be discovered.

Only Option (1) fills all four blanks correctly.

NCERT Extract:
Chemicals, Enzymes and other Bioactive Molecules – “Microbes are also used for commercial and industrial production of certain chemicals like organic acids, alcohols and enzymes. Examples of acid producers are Aspergillus niger (a fungus) of citric acid, Acetobacter aceti (a bacterium) of acetic acid; Clostridium butylicum (a bacterium) of butyric acid and Lactobacillus (a bacterium) of lactic acid.”
Chemicals, Enzymes and other Bioactive Molecules – “… Another bioactive molecule, cyclosporin A, that is used as an immunosuppressive agent in organ-transplant patients, is produced by the fungus Trichoderma polysporum.”
Antibiotics – “… He found out that it was due to a chemical produced by the mould and he named it Penicillin after the mould Penicillium notatum.”