English Translation
Your hat looks silly.
Why is 〝seu〟incorrect？
Every cloze only has one “official” answer, even though there may be other equally valid answers. So I wouldn’t use the word “incorrect”.
By the way, I had expected the possessive to be preceded by the article, “o”.
English Translation
Your hat looks silly.
When I tried this question for the first time, I chose 〝seu〟and it wasn’t correct.