What is one way to control ad frequencies across multiple insertion orders?

• Set campaign-level frequency caps
• Assign a frequency cap to each creative
• Create insertion order budget segments
• Set recency targeting

Correct answer is

• Set campaign-level frequency caps

Explanation: Campaign-level frequency caps work across multiple insertion orders. If you set a frequency cap in a campaign, serving will stop once the first cap at any level (campaign, insertion order, or line item) is reached. If you don’t set a cap at the campaign level, you can control frequency at the insertion order- and line item-levels.
Read more here: https://support.google.com/displayvideo/answer/7205081