This is a bit similar to another question already asked but I think the context is somewhat different.
I was taking a sample Cambridge CPE test and one of the tasks involved was to change a sentence using a given word, changing neither the sentence's meaning nor the word's.
The sentence was:
The manager refused to discuss his decision further.
The word to use was "open".
The manager stated that his decision [insert answer here] discussion.
My answer was:
The manager stated that his decision [was not open for further] discussion.
The answer key says [was not open to further].
Was my answer also correct or not?