单选题 The incident mentioned in the passage originated as early as 1983 when ______.

A、 the virus which causes AIDS were about to be discovered
B、 the Japanese companies were permitted to import untreated blood products from U.S
C、 the Japanese government's bureaucrats were severely attacked
D、 the Japanese Health and Welfare Ministry adhered to the policy that no untreated blood should be imported from abroad

【正确答案】 D

【答案解析】文章第4至5段明确指出了答案。