The answer is D. Last year, zoo visitors donated over $1.3 million to protect endangered animals.
Explanation:
To support a claim implies providing examples, reasons, or evidence that show the main claim is true. In the case of the claim presented, one of the most effective ways to support this is to include a statement or evidence showing how people learned by visiting zoos or any positive effect derived from visiting zoos. In this context, option D is the most appropriate because only because people went to the zoos they became aware of the situation of endangered animals and decided to donate to help these species.
Definitely B, slander doesn’t get your point across the way you want it to come across. the other options are all good, professional, respectful ways to voice your opinion
