【单选题】听力原文: The United States has begun to review Russian documents about the life and death of former President John F. Kennedy and expected to release them once the review is complete, the White House sai...
A.
they cover the whole story of the former US president.
B.
the assassin used to live in the former Soviet Union.
C.
they are the only official documents released about Kennedy.
D.
they solved the mystery surrounding Kennedy's assassination.