(A) whether tourists will continue to visit game parks and see rhinoceroses after their horns are
(B) whether tourists will continue to visit game parks to see one once their horns are
(C) whether tourists will continue to visit game parks to see rhinoceroses once the animals horns have been
(D) if tourists will continue to visit game parks and see rhinoceroses once the animals horns are
(E) if tourists will continue to visit game parks to see one after the animals horns have been
Solution:
Idioms + Pronoun*
D and E can be eliminated because whether is always better than if.
A and B can be eliminated because their in these options does not have a clear reference; it may refer to the tourists as well.
C is the best choice.
Sentence Correction - 1000 Questions with Solution: