Managerial accounts are prepared primarily for internal decision-making, planning, control, and performance evaluation. Unlike external financial statements, they are not required to follow a fixed external reporting format or be prepared for general public users. They should be tailored to the needs of the specific internal users who rely on them, such as department managers, senior executives, project leaders, or cost center owners. Option A is incorrect because managerial reports may be prepared daily, weekly, monthly, quarterly, or on demand depending on operational needs. Option B is not a defining requirement because external auditors verify external financial reports, not necessarily internal managerial accounts. Option C is too broad because specialized managerial reports may only be understandable to relevant users. Therefore, Option D is correct.