Which metrics section displays changes made to your campaign or ad group,and which optimization s were made and by whom?

Activity history is the correct answer because it provides a detailed log of all changes made to a campaign or ad group, including who made the changes and what optimizations were implemented. This feature is crucial for auditing, understanding performance shifts, and ensuring accountability within a team. Breakdown by device shows performance metrics segmented by the type of device users are on (e.g., mobile, desktop), not changes made. Breakdown by creative displays performance based on different ad creatives used, not the historical modifications to campaign settings.