​An English auction is

A) ​A sealed auction
B) An oral auction
C) An auction where bidders submit decreasing bids
D) ​All of the above

English Auction

A public sale method where bids are openly made and raised until no higher bid is offered, with the highest bidder purchasing the item.

Sealed Auction

An auction format in which all bids are submitted simultaneously in sealed envelopes, and the highest bid wins without bidders knowing the bid amounts of others.

Oral Auction

In this auction type, bidders submit increasing bids until only one bidder remains. The item is awarded to the last remaining bidder.