【单选题】

{{I}} Questions 18 ～ 21 are based on a monologue about travel.{{/I}} Which of the following describes a "package tour"

A、It includes everything offered by airlines, railroads, bus lines or some other travel companies.
B．It refers to the sightseeing trips only.
C．It is the trips arranged by the travel agencies.
D．It is the trips organized for young people about fourteen years olD、