5. Sale by auction. An auction has the following characteristics:
a. It is an open sale which gives opportunity to the public to bid price.
b. There are three parties involved: the seller (the owner), the auctioneer and the buyer (the public).
c. The highest bidder will get the property.
d. The sale is complete when the auctioneer announces its completion by the fall of hammer or in any other customary manner. Until such announcement is made any bidder may revoke his bid.