question:  What is Androka’s motivation for using the zone of silence?
context: SILENCE IS—DEADLY By Bertrand L. Shurtleff Radio is an absolute necessity in modern organization—and particularly in modern naval organization. He moved slowly to the door, paused there, and flung a backward glance at the man in the cabin with him—Zukor Androka, the elderly Czech scientist, a guest of the United States navy, here aboard the cruiser Comerford . Androka had arrived on board the Comerford the day before she sailed from Norfolk. With him came a boatload of scientific apparatus and equipment, including a number of things that looked like oxygen tanks, which were now stored in the forward hold. Androka had watched over his treasures with the jealous care of a mother hen, and spent hours daily in the room in the superstructure that had been assigned as his laboratory. This storm—" Curtis threw his arm around Nelson's dripping shoulders. "But this storm, sir!" Nelson avoided Curtis' friendly eyes and slipped out from under his arm. Nelson's estimate, I'm checking back," he declared, frowning at the two papers and hastily rechecking his own figures. With all these rocks and islets—" "Radio?" repeated the little Czech, thrusting his face between the other two, in his independent fashion that ignored ship's discipline. It will be no more than Hitler can get when Zukor Androka decrees silence over the German airways! Then he hastened to the radio room, with Nelson at his heels, and the Czech trotting along behind. I have shattered them around your ship, just as I can eventually shatter them all over Central Europe! For the next two hours, no radio messages can enter or leave my zone of radio silence—of refracted radio waves, set up by my little station on one of the neighboring islets!" If you're not talking nonsense, call off your dogs till we learn just where we are!" I have given orders to my assistant that he must keep two hours of radio silence! the operator intoned, winking at the two officers over Androka's discomfiture, and asked for the bearings.
output:  He is helping the Nazi war effort
options:  He is helping the Nazi war effort  He is helping the American Navy.  He is doing Bob Curtis a favor by helping his ship be the most successful in the Navy.  He is planning revenge against the Nazis for harming his family.