Option C 'Hijacker' is the word for the phrase 'one who forcibly seizes control of a bus or an aircraft'. Option A 'Pirate' means one who attacks and robs the ship in a sea. Option B 'Swindler' means a fraud. Option D 'Pilferer' means a thief who steals without violence. Thus, options A, B and D are incorrect and correct answer is option C, Hijacker..