Final answer:
Block 13 of the DA Form 3161 is signed by the individual receiving the property during a lateral transfer, indicating receipt and assumption of responsibility for the items.
Step-by-step explanation:
When the DA Form 3161 is used as a lateral transfer document for the transfer of property between units or individuals within the same command, block 13 of the form is signed by the individual receiving the property. This person is typically assuming responsibility for the items and is acknowledging receipt of the materials or equipment. The purpose of this signature is to establish clear accountability and record keeping within the military supply system.