Read the excerpt from The Dark Game: True Spy Stories from Invisible Ink to CIA Moles.

The CIA planning was extraordinary. Questions were asked. Problems were anticipated, solutions suggested. With information provided by an informant in the Soviet state-run telephone operation, the U.S. knew that the spot they needed to reach with the tunnel was under Schonefelder Chaussee, a major highway that ran along the southern edge of Berlin.

Which statement best describes the author’s viewpoint in the passage?

The US government planned a spy mission in Eastern Germany to obtain information.
The US government’s skillful use of research and intelligence enabled a vital spy mission.
The United States worked with other Allied countries to create a tunnel under a highway in Berlin.
The United States violated international rules of diplomacy when spying on the Russians in Berlin.

The US government’s skillful use of research and intelligence enabled a vital spy mission.