Which of the following is an example of a ?single-price

monopoly??

A.

Electric companies charge a higher electricity price per unitduring peak times of the day.

B.

DeBeers sells diamonds of the same quality to all its customersat the same price.

C.

Safeway sells most of its products at a higher price thanKroger.

D.

Glaxo can raise the price of some of its drugs due to anincrease in demand.