John Primo, the Senior Auditor at Delahanty, Forbes, CA's Was

John Primo, the senior auditor at Delahanty, Forbes, CA's was planning for the audit of Canadian Light Source (CLS) and decided to use benchmarking as an analytical procedure. His manager agreed with John's approach and suggested information sources that would ensure the reliability of the data for his benchmarking exercise.
As John walked out of the office he ran into Gina Stevenson, a newly hired auditor. He congratulated her on her decision to use a substantive approach to her accounts receivable section of the audit program.
Gina was also going to be reviewing certain internal controls in the CLS audit program. She asked him to whom she should report weaknesses in the client's internal controls.
Required:
a) Which information sources are generally considered to be reliable when conducting benchmarking exercises?
b) What circumstances would have made Gina use a substantive approach?
c) To whom will Gina report weaknesses in a client's system of internal controls?