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 30 minutes 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 into 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 10 minutes before it is scheduled to take off