Write an essay about the ethics of keeping animals in zoos.
Which of the choices below is the best implied thesis statement for the prompt?

A. I think zoos are creepy.

B. Zoos have changed from a collection of small, bare cages to spacious enclosures that mimic natural habitats.

C. Zoos are immoral because entertaining and even educating humans does not justify imprisoning animals in unnatural environments

D. Many people say that zoos are important but others disagree.