What aspect of a fire support plan addresses potential unexpected situations?

The correct choice is contingency measures, as they specifically focus on preparing for unforeseen events that may arise during an operation. Contingency measures are designed as part of a fire support plan to ensure that there are predefined actions and responses in place, which can be implemented if unexpected situations occur. This can include scenarios such as changes in enemy tactics, the need for immediate reallocation of resources, or environmental factors that disrupt the planned operation. By incorporating these measures, the fire support plan becomes more resilient and adaptable to changing conditions on the battlefield.

Other components such as communication plans, target identification, and operational planning play vital roles in the overall execution of military operations but do not directly address the aspect of preparing for unexpected situations in the same way that contingency measures do. Communication plans focus on how information will be exchanged, target identification deals with recognizing and designating targets, and operational planning involves the broader strategic and tactical considerations for the mission. While all these elements are important, they do not specifically target the need for adaptability in the face of the unpredictable.