During the translation process, these possible answers were displayed:
>
The best answer is:
La prosperidad es representada por el buey [> thus, my answer "está representada" was marked wrong]
You could also say:
La prosperidad es representada con el buey,
Or also:
La prosperidad es simbolizada por el buey,
Or also:
La bonanza está representada con el buey,
- . - . - . -
It seemed to me that this particular passive construction focussed on the *result* rather than the action, so I used "estar"... It is interesting that you do allow the use of an "estar" passive with "bonanza", but not with the others; (is there therefore something different about the word "bonanza"?)
- . - . - . -
However, in the opening sentence: "El año chino es representado cada año con un animal", I think I can see how in this particular sentence we are focussing on the action (rather than the result).
- . - . - . -
We discussed this point in the Q&A of Forming the Spanish passive voice with ser + participle (+ por) (passive - simple tenses) - and I mentioned it again in Forming the Spanish passive voice with ser + participle (+ por) (passive - simple tenses)