According to the IAB, an advertiser may cancel any guaranteed vendor order with how many days prior written notice?

The correct answer is 14 days. In the context of digital media buying and planning, the IAB guidelines stipulate that advertisers are typically required to provide a 14-day prior written notice to cancel any guaranteed vendor order. This timeframe allows both the advertiser and the vendor to manage their resources and account for any adjustments in campaign planning.

Understanding this concept is crucial for effective campaign management and ensuring that both parties have reasonable expectations regarding cancellations. It also emphasizes the importance of communication and planning in the digital advertising ecosystem, where timely adjustments are often necessary for maintaining campaign effectiveness and budget management.