What Is the Difference Between a Reverse Auction and Mass

What is the difference between a reverse auction and mass customization?

A) Reverse auction is most often found in B2B whereas mass customization is often found in B2C.
B) Reverse auction requires a bid from consumers whereas mass customization requires a bid from suppliers.
C) Mass customization require a click-and-mortar environment;reverse auctions do not.
D) Mass customization can sell digital products;reverse auctions sell commoditylike products.