except for vs except

Hi~ everyone.

I have a question the difference between 'except for' and 'except'. Would you take a look at the follwing sentences?

A.Clarissa could think of nothing to say except that she was so sorry.
1.Clarissa could think of nothing to say except for the word, 'sorry'.
2.Clarissa could think of nothing to say except the word, 'sorry'.

B.Clarissa could have thought of something to say except that she was so sorry.
1.Clarissa could have thought of something to say except for the word, 'sorry'.
2.Clarissa could have thought of something to say except the word, 'sorry'.

I was wondering which was correct when we pharaprase except- leading clauses into prepositional phrases, or both were acceptible under the condition of A and B. As to A example, I have got a baseless feeling that both could be possible, but as for B, I am not be able to have a good idea. Which is right?

Many thanks in advance.