This movie was b. Dave.
It's about Dave Kovic ( hence the name of the movie) who is agency worker that has a side-job of substituting the president in public appearances.
Earth can be considered as a closed system, since it only receives sunlight (energy), while the overall mass stays constant, without (almost) any exchange from space. Another example of a closed system is a saucepan or frying pan, on a stove, when its lid is closed.
I think its C, because the US wanted to isolate more and more from other countries.
