单项选择题
A．promote a special flight program B．recommend long distights C．introduce different airlines 2 group D．describe an alliance flights
A．offers the lowest prices to its passengers B．keeps passengers better informed of its operations C．offers better services than any of its member airlines alone D．is intended to make round-the-world trips more challenging
A．its detailed travel information B．its unique booking system C．its longest business flights D．its global service network