 Of all the characters, who is seen as an antagonist in the article?
SILENCE IS—DEADLY By Bertrand L. Shurtleff Radio is an absolute necessity in modern organization—and particularly in modern naval organization. [Transcriber's Note: This etext was produced from Astounding Science-Fiction April 1942. Extensive research did not uncover any evidence that the U.S. copyright on this publication was renewed.] That would be Nelson, his navigating officer. Nelson always knocked that way—like a man in an external state of jitters over nothing at all. 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 . The wizened face of the older man was molded in intent lines of concentration, as his bushy gray head bent over his drawing board. 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. Sometimes, Curtis thought old Androka was a bit wacky—a scientist whose mind had been turned by the horror that had come to his country under the domination of the Nazi gestapo . Overhead, the sky was a storm-racked mass of clouds, broken in one spot by a tiny patch of starlit blue. It was Nelson, his shaggy blond brows drawn scowlingly down over his pale eyes; his thin face a mass of tense lines; his big hands fumbling at the neck of his slicker. He was overfriendly with a black-browed bos'n's mate named Joe Bradford—the worst trouble maker on board. Nevertheless, his taut face, restless, searching eyes, and eternally nervous manner got Curtis' goat. Nelson shouldered his way inside, and stood there in his dripping oilskins, blinking his eyes against the yellow light.
 Androka, because his actions severely inconvenienced the crew of the ship.
 Androka's assistant because he turned off the radio.  Commander Curtis because he rarely complied with the other crew members.  The radio man on the ship because he could not complete Commander Curtis's orders.  Androka, because his actions severely inconvenienced the crew of the ship.