听力原文： A passenger jet headed for New York City was forced to land at Halifax, Canada this morning. The plane's transponder was broadcasting a signal indicating it had been hijacked. The Virgin Atlantic flight from London's Heathrow Airport was midway across the Atlantic when air traffic control officials in the US started receiving its signal: a signal which carried a special code indicating them was a hijacking in progress. Canadian fighter jets operating under NORAD, the joint Canada-US command, were scrambled to intercept the jet. According to NORAD, the pilots of the passenger jet repeatedly radioed in to tell controllers they were not being hijacked. But US officials erred on the side of caution. After the plane landed, armed police boarded it to ensure there were no hijackers. It was determined that the plane's transponder had mal-functioned, and was mistakenly transmitting code "7500" for hijacking.
Why the passenger jet was forced to land at Halifax, Canada？

A. Some passengers would get off the plane in Canada.
B. There was something wrong about the plane and it could not fly again.
C. Because there were criminals on the jet plane. '
D. Because it had been thought that the jet had been hijacked.