A Few Years Ago, If You Wanted the Lowest Rate

A few years ago, if you wanted the lowest rate for a telephone call, you either called after five pm or during the weekends. Today, the phone companies advertise a "seven-cents-a-minute" or lower charge all the time. There is no special time that rates are lower. From this example, it can be best judged that phone companies are no longer

A) concerned about strategies applied by competitors.
B) concerned about profit maximization.
C) using pricing effective strategies.
D) using off-peak pricing.