[单项选择] Mad Cow Disease in Canada For years, Canada had been virtually free of mad cow disease. But in May 2003, veterinary officials in Alberta confirmed that a sick cow sent to a slaughterhouse in January of that year had been inspected, found to be substandard, and removed so that it would not end up as food for humans or other animals. The carcass was, however, sent to a processing plant for rendering into oils. Its head was kept for testing. Samples were sent to the world testing laboratories in the U. K. , which confirmed the case of mad cow. "What is important is that the system worked," said Shirley McClellan, Alberta’’s agriculture minister at the time. "We have a very thorough and respected inspection system." She was insistent to remind the public that the disease is not contagious within a herd. But McClellan’’s assurances didn’’t stop the U. S. , Japan, South Korea, Australia and other countries from imposing temporary import bans of Canad
A. Y
B. N
C. NG