Which of the following packages can be shipped by USPS retail ground?

USPS Retail Ground is a shipping service that is specifically designed for shipping larger and heavier packages that do not require the speed of Priority Mail or Express services. ORM-D (Other Regulated Materials-Domestic) packages fall under this category. ORM-D items are materials that, although considered hazardous, can be shipped under certain conditions. USPS allows these packages to be sent using Retail Ground, making it a suitable shipping option for such items, provided they comply with the regulations.

First Class mail is intended for lightweight letters and small packages; Priority mail is a faster service designed for packages needing expedited delivery, and Overnight Express packages are explicitly meant for next-day delivery. None of these options align with the purpose of USPS Retail Ground shipping, which specifically accommodates packages that do not meet the criteria for faster or weight-restricted services. Therefore, ORM-D packages represent the correct choice, as they can uniquely utilize the Retail Ground service for shipping, adhering to USPS guidelines for such materials.