According to Economists Frank and Cook,one Reason There Are More

According to economists Frank and Cook,one reason there are more winner-take-all markets today than in the past is because

A) government has limited the choices that people can make when they are choosing what to buy.
B) changes in technology, communications, and transportation costs have made it possible for consumers to buy from a small handful of "the best" suppliers in the world.
C) changes in technology have lowered prices.
D) of the importance that today is placed on ideas instead of things.
E) a and b