b$)$ Discuss your thoughts on the possible overall root cause of contamination $($physical and microbiological$)$ that increased as the concentration of the API increased. Include this in the $$Probable Root Cause$$ section of the investigation report.

c$)$ Identify possible corrective actions which could be implemented to prevent this type of failure from recurring, and include in the $$Corrective Actions$$ and $$Preventative Actions$$ sections of the investigation report.