As evidenced by

A. She has become known for the power of her writing, as evidenced by the popularity of her new book.

Q1) In sentence A, what does "as evidenced" grammatically modify?

1."as evidenced" grammatically modifies "She"

2."as evidenced" grammatically modifies "She has become known for the power of her writing"

I think that number 2 is the correct answer because "as evidenced" can be thought of as the shortened form of "as is evidenced".

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Q2) And is sentence A correct English even if there isn't "is" as in "as (is) evidenced" ?

A. She has become known for the power of her writing, as evidenced by the popularity of her new book.

Q3) Perhaps, in sentence A, is "as" used like a relative pronoun that refers to "She has become known for the power of her writing"?

What do you think?