Final answer:
Auditors, regulators, clients, and shareholders may require a written report regarding the assertion of another party.
Step-by-step explanation:
A) Auditors are required to have a written report regarding the assertion of another party. Auditors are professionals who review financial statements and provide an opinion on their accuracy and compliance with relevant accounting standards. The written report is commonly known as the auditor's report.
B) Regulators, such as government agencies or professional bodies, may require auditors to submit a written report for their review and assessment of the auditor's work.
C) Clients may request auditors to prepare written reports regarding the assertion of another party, for example, when they need assurance on the financial statements of a subsidiary or a supplier.
D) Shareholders, although not required, may also request auditors to provide a written report on a specific matter if they have concerns or doubts about the assertions made by another party.