FOR THISFICTIONALFACT PATTERN, INDICATE WHO HOLDS THE BURDEN OF PROOF IN THE CASE AND WHAT LEVEL OF NEGLIGENCE/LIABILITY MUST BE PROVED TO HOLD THE AUDITOR ACCOUNTABLE, AND WHY:

United Airlines is a public company whose audited financial statements are filed annually as required by the SEC.United has 52 Boeing 777's in its fleet whose engines fly off in midair due to lack of maintenance.This has happened several times to United over the past few years.The FAA permanently grounded United's 777 fleet after the latest incident, and United was forced to write off the value of the planes.Investors sued United and its auditors claiming that the impairment charge should have been recorded much earlier.