According to guidelines, where should markings be placed for special services on correspondence?

The placement of markings for special services, such as "Certified" or "Registered," is critical for proper handling and processing of correspondence. According to established guidelines, these markings should be placed above the address to ensure they are immediately visible to postal workers and handlers. This positioning allows the markings to clearly indicate the type of service required, facilitating timely and accurate delivery while ensuring that the special handling instructions are recognized before the mail is processed. Using this method minimizes the risk of miscommunication regarding the handling of the correspondence.

In contrast, placing markings below the address, at the bottom left corner, or to the left of the return address does not adequately highlight the special service, which could lead to delays or mishandling of the mail. Thus, the correct answer emphasizes that special service markings must be positioned above the address for maximum visibility and efficiency in mail handling.