How much mail should a carrier pick up when casing flats?

The correct answer indicates that a carrier should pick up about 50 pieces in the left arm while distributing with the right hand. This method is effective because it utilizes the carrier's body mechanics efficiently, allowing for a good balance between carrying a substantial number of flats and being able to distribute them effectively.

Picking up flats in this manner ensures that the carrier can manage a significant volume of mail with minimal movement, which is crucial for maintaining a steady workflow. Utilizing the non-dominant arm for holding a larger quantity of mail frees up the dominant hand for sorting and delivering, promoting a more organized and streamlined approach to handling deliveries.

This technique also helps in ensuring that the carrier can maintain their pace and efficiency throughout their route, which is vital in the context of daily mail delivery operations. Lower numbers in the other options would likely lead to more trips back to the mail case, thereby reducing overall efficiency.