Question #$1$:

Specification: Perform conceptual design for the Auction requirements below. You must generate both an ER diagram and a specification that includes additional constraints not shown on the diagram. The specification should be written in English. If you believe that you need to make additional assumptions, clearly state them.

An auction Web site has items for sale that are provided by sellers. Each item has an opening price, a description, and an ending time. Customers submit bids. The highest, earliest bid submitted before the ending time is the winning bid and the item is sold to the bidder. Each seller must pay the auction company $5\%$ of the winning bid. The auction company wants to be able to analyze the sales behavior of its customers and sellers and so must keep track of all bids and sales.

Questions: Design and draw an ER diagram that captures the information about the Auction. Be sure to indicate any key, cardinality, and participation constraints.