What Occurs When the Retail Sector Is Very Concentrated

What occurs when the retail sector is very concentrated?

A) It is more expensive for a firm to make contact with each individual retailer.
B) It makes sense for a firm to deal directly with retailers,cutting out wholesalers.
C) A relatively large sales force is required to deal with the retail sector.
D) The channels of distribution tend to be long.
E) The growth of wholesalers is promoted.