An advertiser is running an awareness campaign with custom bidding and its goal is to spend the budget in full with a $2.50 cost per mille (CPM). Currently, the campaign is pacing at 100%, but the CPM is $2.55. What optimization levers will get the advertiser's campaign closer to that $2.50 goal?

The correct answer is setting the custom bid to $2.45 and monitoring. Since the campaign is already pacing at 100% and slightly over the target CPM, lowering the custom bid slightly will help reduce the CPM without significantly impacting delivery. You should monitor closely to ensure the campaign continues to spend its budget. Turning off expanded targeting to narrow targeting would likely decrease reach and potentially hinder budget spend, which is not the primary goal here as the campaign is already pacing at 100%. Pausing the interest with the highest spend could drastically reduce reach and prevent the campaign from spending its full budget. Setting the custom bid to $2.75 would increase the CPM further, moving it away from the $2.50 goal.