I created three marketing campaigns, two of them are being display on all pages, while the third one is displayed with the others only on the product page. This is how I display the campaigns from C# code

var campaignItems = MarketingLibrary.GetTargetedCampaignItems();

Ucommerce does it correctly, but I want to know how Ucommerce knows that the two campaigns are for all page and that one is only for the product page and control it through my C# code.