Final answer:
The key guideline from the Special Committee on Financial Reporting is that information that significantly harms a company's competitive position should not be required to be reported.
Step-by-step explanation:
The key guideline from the Special Committee on Financial Reporting regarding information that could harm a company's competitive position is C) Information that significantly harms the company's competitive position should not be required to be reported. This means that if disclosing certain information would put a company at a significant disadvantage in the market, they are not required to report it. This guideline recognizes the importance of protecting a company's competitive position while still emphasizing the need for transparency in financial reporting.