What should be left blank on the DD Form 285 cards prepared by the unit commander or postal officer?

The correct option indicates that blocks 1, 2, and 10 should be left blank on the DD Form 285 cards prepared by the unit commander or postal officer. These specific blocks are typically designated for information that may not be necessary for all submissions or are intended for an automated system or administrative processing that does not require completion by the individual filling out the form.

By leaving these blocks blank, the form remains compliant with standard processing procedures and streamlines data collection, ensuring that only pertinent information is communicated. This can help to minimize errors or confusion that could arise from unnecessary entries in those fields, making the overall process more efficient and organized.