Read the excerpt below and answer the question.
The human beings did not hate Animal Farm any less now that it was prospering; indeed, they hated it more than ever. Every human being held it as an article of faith that the farm would go bankrupt sooner or later, and, above all, that the windmill would be a failure.
In this excerpt, the phrase "article of faith" is an example of a(n) _____.
A.analogy
B.metaphor
C.personification
D.simile