In What Sense Is It Now Possible for a Country

In what sense is it now possible for a country to be "occupied" by an invisible invader that arrives through airwaves and wireless networks?

A) Spy satellites and other communications technology are increasingly advanced.
B) The U.S. government can eavesdrop on almost any form of modern communication.
C) Global positioning systems have allowed detailed mapping of previously inaccessible places.
D) It's almost impossible to block foreign countries' satellite broadcasts and Internet transmissions.
E) Many nations now use their militaries to transmit information.