GMAT Sentence Correction (SC) | Re: So dogged were Frances Perkins investigations of the garment

Hi guys,

I actually got this question on a GMATPrep CAT and unfortunately had an error.

Now I directly saw the 'So X, so Y' structure, but thought (E) included an error, because it had "her" referring back to "Frances Perkins' ". Now I thought that her can refer back to a noun/subject and while in this case it appears it is referring back to Frances Perkins, it is referring back to the possessive "Frances Perkins' ". Is this possible and in what cases can we use
...

---