What is the maximum size permitted for a flat shipment?

The maximum size permitted for a flat shipment is determined by specific guidelines set forth by postal services to ensure efficient processing and delivery. The correct choice indicates a package that meets these regulations, specifically maintaining limits on dimensions that define flat mail.

In this case, the dimensions of 12" x 15" x 3/4" fall within the acceptable limits for flat shipments. Flat shipments, which typically include items like brochures or magazines, must not exceed a thickness of 3/4 of an inch. Furthermore, the length and height dimensions are also designed to comply with the larger size capacities for flats, which can often be larger than standard envelopes but must still maintain specific measurements.

The other options either exceed the permissible dimensions for flat mail or fall short of the required measurements, which contributes to a systematic categorization and processing of mail in a way that maximizes efficiency for postal operations. By adhering to these size restrictions, mail can be sent in an appropriate format that facilitates easier handling and transport.