Which of the following organism produces statins?

The correct answer is Monascus purpureus

Explanation:

• Statins produced by the yeast Monascus purpureus have been commercialised as blood-cholesterol lowering agents. It acts by competitively inhibiting the enzyme responsible for synthesis of cholesterol. 
• Cyclosporin A, that is used as an immunosuppressive agent in organ-transplant patients, is produced by the fungus Trichoderma polysporum.
• Aspergillus niger is known for producing Citric acid.
• Clostridium butylicum is known for producing Butyric acid.