An advertiser is looking to secure inventory on the homepage of xyz.com and wants to buy it for $20 CPM. Entering into which type of private marketplace deal with the publisher would guarantee their inventory at a fixed price?

The correct answer is Preferred deal because in this type of private marketplace (PMP) deal, the advertiser and publisher agree on a fixed price for inventory, such as $20 CPM, without any bidding involved. The preferred deal allows the advertiser to secure the inventory at this predetermined price, ensuring they have access to the homepage inventory of xyz.com at that fixed rate. This is in contrast to a private auction deal, where multiple advertisers can bid, potentially driving up the price, and other options like "Advertiser first deal" and "Prime day deal" are not standard PMP deal types associated with guaranteed inventory at fixed prices.