Don Pablo, the Senior Auditor at Delahanty, Forbes, CPAs Was

Don Pablo, the senior auditor at Delahanty, Forbes, CPAs was planning for the audit of Winnipeg Lighting Showcase (WLS) and decided to use benchmarking as an analytical procedure. His manager agreed with Don's approach and suggested information sources that would ensure the reliability of the data for his benchmarking exercise.
As Don walked out of the office he ran into Helena Bodson, a newly hired auditor. He congratulated her on her decision to use a substantive approach to her accounts receivable section of the audit program.
Helena was also going to be reviewing certain internal controls in the WLS 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 Helena use a substantive approach?
c) To whom will Helena report weaknesses in a client's system of internal controls?