Critical Reasoning

John was flying from San Francisco to New York with a connecting flight in Chicago on the same airline. Chicago's airport is one of the largest in the world, consisting of several small stand-alone terminals connected by trams, John's plane arrived on time. John was positive he would make his connecting flight thirty min- utes later, because _


Which of the following most logically completes the argument above?
(A) John's airline is known for always being on time
(B) a number of other passengers on John's first flight were also scheduled to take
John's connecting flight
(C) at the airport in Chicago, airlines always fly in and out of the same terminal
(D)John knew there was another flight to New York scheduled for one hour after
the connecting flight he was scheduled to take
(E) the airline generally closes the doors of a particular flight ten minutes before it is
scheduled to take off

Mine doubt is if i think of the connecting flight as a different flight than the one on which John has come then , option C will not look favourable.There is nothing in the argument to assume that the flight is going to be same one. Can someone pls explain this ?

Note: By POE i was able to get the correct answer , but am more looking to have above doubt clarified.

OA C