After looking over a report in Campaign Manager 360 about a client's new campaign, you observe that the default ads run more frequently than the new ads for the campaign. What could cause this to happen?

Geographic and language targeting can significantly restrict the audience for new ads. If the new ads have more specific targeting criteria than the default ads, they will have fewer opportunities to be served, leading to the default ads running more frequently. Including three different creatives (A) doesn't inherently cause default ads to run more often; it simply provides more creative options. Allowing both ad types to run across various sites and platforms (B) would generally increase opportunities for both, not favor defaults. Setting the priority of a new ad to "2" (C) would typically make it run before a standard ad (which usually has a lower priority like 1 or 0), not less frequently.