Establishment of Biological Reserves Has Shown That They Can Be

Establishment of biological reserves has shown that they can be very important for the recovery of endangered species. In the case of the white rhino the establishment of a reserve has helped:

A) increase the white rhino population more than a hundredfold.
B) maintain the white rhino population size at pre-reserve numbers.
C) increase the white rhino population outside of the reserve.
D) maintain the white rhino population outside the reserve.