It is C
Whether is better than if when you have two options in this case you have either keep visiting or not doing so anymore, so the options with If are eliminated.
Then we see a mistake with "their" Pronoun Error, always when you see their, its, them you have to verify that these pronouns agree with the correct subject, so here that specific "their" you don't know wheter it corresponds to rhinoceroses or tourists' HORNES! (Something that sounds horrible but true)
B has the same problem that A has ambiguous "their" pronoun.
So C corrects this error making clearer that the animals' hornes are trimmed
I hope this helps
A is ambigious.How is that so?
whether tourists will continue to visit game parks and see rhinoceroses after their horns are
How can their refer to the people?Its already mentioned that the rhinos are getting their horns trimmed!Pls explain.