It Has Become More Difficult to Create Value in the Travel

It has become more difficult to create value in the travel agency industry because

A) more and more customers purchase airline tickets directly from web sites rather than from travel agents.
B) travel agents primarily arrange domestic travel and today people tend more toward international travel.
C) travelers are migrating toward cruises for vacations and are avoiding airline flights.
D) airline fares have become much easier to understand than they were a few years ago.