你的同事要放送 YouTube 連網電視 (CTV) 廣告活動，並指定熱門優質發布商的廣告空間，這是他們第一次設定這類廣告活動，希望能正確設定。 請問他們應調整哪項 Display & Video 360 廣告活動設定，確保廣告活動順利放送？

The correct answer is to set the campaign to run 15-second, 30-second, and 60-second ads. This is crucial because YouTube CTV inventory often has varying ad slot durations. By preparing ads of these common lengths, the campaign maximizes its chances of filling available inventory across different publishers and ad breaks, ensuring smooth delivery. Limiting line items to specific device inventory (e.g., only smart TVs) might restrict reach unnecessarily, as CTV can encompass various devices. Adding brand safety targeting is generally good practice but not a setting adjustment specifically for ensuring smooth delivery of a first-time YouTube CTV campaign; it's a standard optimization. Setting line items for CTV app inventory and targeting both programmatic guaranteed and open auction is a good strategy for inventory acquisition, but it doesn't directly address the smooth delivery aspect as effectively as having appropriate ad lengths for the available slots.