Which of the following should be a required criterion of the security guard's post orders?

The correct choice emphasizes that post orders for security guards should be written at the lowest level possible. This means that the orders need to be clear, concise, and easy for all personnel to understand, regardless of their educational or professional background. Writing orders at this basic level ensures that all security personnel can comprehend and effectively execute their duties without misinterpretation, which is essential for maintaining security and safety.

When post orders are accessible and straightforward, it increases compliance and adherence among the security staff. A lack of clarity can lead to confusion and ineffective responses to security situations, potentially putting individuals and the organization at risk. Thus, establishing a foundational level of understanding is critical for successful security operations.

The other options, while they may have some relevance in certain contexts, do not hold the fundamental importance that clarity and simplicity provide for effective operational execution.