How Is the Supreme Court's Ruling in Bartkus V

How is the Supreme Court's ruling in Bartkus v. Illinois (1959) significant to the concept of double jeopardy?

A) It decided that if a jury finds the accused not guilty, the prosecution can appeal to have the decision reversed.
B) It decided that a defendant can be acquitted of violating a federal criminal law and then be tried for violating state law.
C) It permitted juries of fewer than 12 persons.
D) It denied juveniles the constitutional right to a jury.