Final answer:
The decision to unmask after a unit has masked can be made by the commanding officer, the highest-ranking soldier, or the unit medic.
Step-by-step explanation:
In a military unit, the decision to unmask after a unit has masked can be made by the commanding officer, the highest-ranking soldier, or the unit medic. These individuals have the authority and responsibility to assess the situation and determine when it is safe to unmask.