If the members are not understanding each other the clarifier/elaborator should start talking or else nothing will be clear to the other members of the group.
Petulant is incorrect because it means that the volunteers were bad - tempered and volunteers usually are generous.
Clear is incorrect because it is stating that the volunteers were understanding when they were gathering over 100 boxes of food.
Both compassionate and resolute would be good answers for this question since resolute means determined and compassionate means a feeling of concern towards others. However, compassionate would be a better choice since the volunteers are putting all this effort in to help the physical needs (food) of the people in the local pantry.
