Sentence Correction (SC) | Re: Beatrix Potter, in her book illustrations, carefully

Both are alright:
In the first case, "which" is used as an object (the doer of the action (she) is the subject, "which" is the object - active voice).
In your example "which" is used as subject (hence passive voice - doer of the action (she) is NOT the subject). Another example:

I have a pet dog,
...

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