The correct answer is D. He wants his audience to see the arrogance of their assumptions about themselves.
Step-by-step explanation:
The book "Gulliver's Travels" by Jonathan Swift tells the story of a traveler called Gulliver who encounter particular societies while he travels to different remote areas. One of the main purposes of the author with this book was to criticize some aspects of the society he did not agree with mainly by using fictional situations and satire in which people or practices are ridiculized to create a critique about them.
In the case of "A Voyage to the Country of the Houyhnhnms" which is a section of this book, the narrator and main character Gullivers arrives to a remote region in which the horses are rational and because of this, they rule over humans who are called Yahoos and lack of the level rationality shown by most humans and because of this they should serve the horses. This society stricken the main character as in Gulliver's country the human rules over horses and not in the opposite way, this questions the level of rationality of humans and the assumptions people made about themselves as the message of the author in this case is that most people are arrogant and consider themselves as superior to other creatures, but this might not be true. Thus, the purpose of "A Voyage to the Country of the Houyhnhnms" by Swift is to make the audience see the arrogance of their assumptions about themselves, especially in terms of superiority and rationality.