Which activity is NOT considered a preparation activity for an attack?

Supply sourcing is not considered a preparation activity for an attack because this activity focuses on logistical support and resource acquisition rather than the immediate tactical preparations necessary for an attack. While ensuring that the logistics are in place is vital for overall mission success, it does not directly involve the maneuvers or operational readiness of troops in the field.

In contrast, rehearsals, troop movements, and precombat checks and inspections are all directly related to preparing forces for an attack. Rehearsals allow units to practice their tactics and ensure they are coordinated. Troop movements are necessary to position forces appropriately for action, and precombat checks and inspections help confirm that personnel and equipment are ready for the upcoming operation. These activities are integral to operational readiness, focusing on the tactical aspects of an impending attack.