Which of these buying method provides advertisers higher priority to inventory?

Fixed price buying provides advertisers with higher priority to inventory because it involves a direct agreement with the publisher or platform for a set price, guaranteeing a certain amount of impressions or placements. This direct negotiation often comes with reserved inventory, ensuring the ad will run as planned. Open auction, conversely, is a real-time bidding process where advertisers compete for ad impressions, and there's no guarantee of winning specific inventory or achieving a desired priority. While open auctions offer flexibility and potentially lower costs, they do not provide the same level of inventory priority as fixed-price deals.