Answer:
The correct option is E. Bring in some elephants of reproductive age from other populations within southern Africa
Explanation:
Inbreeding depression can be described as a phenomenon in which the fitness of a particular kind of species is reduced due to inbreeding of the organisms.
As the Addo National Park contains only a few elephants, hence there are only a few chances of diversification in their breeding patterns. If other elephants are brought into the Park, then there will be more options for breeding and breaking the inbreeding depression.