In a move that could revolutionize the way we buy groceries,Amazon opens its first supermarket without checkouts-human or self-service--to shoppers on Monday.Amazon Go,in Seattle,has been tested by staff for the past year.It uses hundreds of ceiling-mounted cameras and electronic sensors to identify each customer and track what items they select.Purchases are billed to customers'credit cards when they leave the store On entering the store,shoppers walk through gates,swiping their smartphones loaded with the Am-azon Go app.Then they are free to put anything into their own shopping bags.With the help of sensors on the shelves,items are added to customers'Amazon Go account as they pick them up-and delete any they put back.And an electronic receipt is issued as they exit The store opened to employees of the online retail giant in December 2016 and had been expected to allow the public in more quickly.But there were some teething problems with correctly identifying shoppers of similar body types--and children moving items to the wrong places on shelves,according to an Amazon insider.Gianna Puerini said the store had operated well during the test phase Hundreds of infra-red ceiling cameras have been trained over the last year to differentiate between customers as they move around the store,and between items for sale,even those with similar appearances.There are weight sensors on the shelves to help indicate if an item has been taken or put back And some items carry a visual dot code,like a bar code,to help cameras identify them.Amazon isnt offering any information on how accurate the system is.One thing we do know:they're on to the less-than-honest.A New York Times journalist had a go at shoplifting some cans of soft drink,but the system spotted it and put them on his bill Amazon has not said if it will be opening more Go stores,which are separate from the Whole Foods chain that it bought last year for$13.7bn（E10.7bn）.As yet the company has no plans to introduce the technology to the hundreds of Whole Foods stores.However,retailers know that the faster customers can make their purchases,the more likely they are to return.Making the dreaded supermarket queue a thing of the past will give any retailer a huge advantage over its competitors In its third quarter results in October,Amazon for the first time put a figure on the revenues generated by its physical stores:S 1.28bn.Yet almost all of that was generated by Whole Foods.While its stores may not yet be money spinners,analysts have said Amazon is using them to raise brand awareness and promote its Prime membership scheme.Brian Olsavsky,Amazon chief financial officer,recently hinted that rivals should expect more Amazon shops in the months and years ahead You will see more expansion from us-it's still early,so those plans will develop over time,he said in october
In the last paragraph,Brian Olsavsky implies that

A revenues generated by Go shops surpass that of Whole Foods

B there will be more Amazon retailer stores in the future

C Whole Food stores are more competitive than Go shops

D the retailer stores will take place of the Whore Foods