Final answer:
In the case of an auction with a reserve price, the auctioneer calling for bids is presenting an invitation to treat.
Step-by-step explanation:
In the case of an auction with a reserve price, the auctioneer calling for bids is presenting an invitation to treat. An invitation to treat is a preliminary communication that invites a person to negotiate or make an offer, but it is not itself an offer to form a contract. By calling for bids, the auctioneer is initiating the negotiation process to find a price that the buyers are willing to accept.