A growing taste for shark steaks and shark-fin ... ...

According to the passage, a decrease in shark populations

  I.   might cause some fish populations to go unchecked.
  II.   would hamper cancer research.
  III.   to one-quarter the current level would take over a decade to recover from.
(A) II only
(B) ...
(C) ...
(D) ...
(E) ...

*This question is included in Nova Press: Set E - RC Practice