Final answer:
The guideline suggests that management should report only necessary and relevant information for internal decision-making and stakeholder use, avoiding information overload, bias, or sharing competitive advantages.
Step-by-step explanation:
The main idea of the guideline concerning information management should report, other than for financial statements, is C) Management should report only what it knows and needs to manage the business. This approach is centered on the principle of relevance and discretion. Management is expected to disclose information that is pertinent and practical for internal decision-making processes and to stakeholders who rely on the company's managerial reports for insightful data. Reporting all available information or only positive information can lead to information overload or a biased perspective, respectively. Furthermore, disseminating details that could be useful to competitors might jeopardize a company's competitive edge.