At what point does the mortar to be laid announce "1 or 0 mil mortar lay"?

The point at which the mortar to be laid announces "1 or 0 mil mortar lay" is when it is within 1 or 0 mil deflection. This terminology refers to the precision in the placement of the mortar based on adjustments made during the aiming process. The concept is critical in ensuring accuracy for the impact of mortar rounds on the target.

Achieving a 1 or 0 mil deflection signifies that the mortar crew has made fine adjustments and that the weapon is properly aligned with the intended target. It is an indicator of the mortar's readiness for firing, emphasizing the importance of precision in military operations to minimize collateral damage and improve strike effectiveness.

The other options focus on different stages of the mortar crew's workflow, such as completing a deflection check, firing the weapon, or verifying aiming stakes, but they do not pinpoint the specific moment of accuracy that the announcement of "1 or 0 mil mortar lay" represents. Thus, option B accurately captures the essence of readiness in achieving the necessary precision before firing.