Which of the Following Preservation Tactics Would Have the Greatest

Which of the following preservation tactics would have the greatest impact on saving the largest number of species?

A) Preserve a large tract of land that contains source populations of keystone species.
B) Preserve several small tracts of land that contain source populations of keystone species.
C) Preserve a large tract of land that contains sink populations of keystone species.
D) Preserve a large tract of land that contains source populations of flagship species.
E) Preserve multiple small tracts of land that each contain source populations of keystone species.