Final answer:
The auctioneer needs a license to conduct a real estate auction, which means that the correct answer is (b) the auctioneer needs a license.
Step-by-step explanation:
When Bob and Mary decide to purchase a house from a real estate auction, certain licensure requirements must be met. In most jurisdictions, it is the auctioneer who is required to have a license to conduct auctions. This licensure ensures that the auctioneer is knowledgeable about the legal and ethical guidelines that govern auctions. Therefore, the correct answer is (b), that the auctioneer needs a license. It is not typical for the auction house itself to require a separate license, and neither waivers signed by the buyers nor a lack of any license satisfy the legal requirements for conducting real estate auctions.