Answer:
d. Both A&B
Explanation: Auction is a term used in the field of marketing or trading of goods where bidders are allowed to make bids(amount which they intend to pay for a given product) the Product can either be an Artwork or other goods like furniture,Cars, clothes etc.
A common value auction is a type of auction where certain information about the value of a product are available to some bidders and other sets of bidders have other information about the value.
DISPLAYING INFORMATION ABOUT A COMMON VALUE AUCTION IS GOOD FOR THE BIDDERS AS IT REDUCES THE RISK THEY FACE ESPECIALLY BEFORE BUYING THE PRODUCT AND FOR THE AUCTIONEER AS IT HELPS TO ATTRACT MORE BIDDERS.