Final answer:
The need for an external audit is justified because it provides an independent review of a company's financial and operational activities, thereby ensuring the integrity of financial information for stakeholders.
Step-by-step explanation:
Among the options provided, the one that justifies the need for an external audit is C: External audits provide an independent review of financial and operational activities. An external audit is an impartial examination conducted by an outside auditor or accountancy firm. It offers valuable insights and assurance to stakeholders such as investors, creditors, and other interested parties that the company's financial statements are accurate and comply with relevant laws and regulations.
External audits are not universally required by law for all healthcare organizations, as stated in option A, but certain public companies and other entities may be legally required to have their financial statements audited. Option B is incorrect because the intention of an external audit is not to cover up fraudulent activities, but rather to detect and prevent them. Lastly, option D is also wrong because the primary purpose of an external audit is not for marketing but to ensure the integrity and reliability of financial information.