Sentence Correction

While depressed property values can hurt some large investors, [they are potentially devastating for homeowners, whose] equity- in many cases representing a life's savings- can plunge or even disappear.

A)
B) They can potentially devastate homeowners in that their
C) for homeowners they are potentially devestating, because their
D) for homeowners, it is potentially devestating in that their
E) it can potentially devastate homeowners, whose

Oa isA

I was just wondering how the word they refers exactly to depressed property values. I thought it was ambiguous because of the two antecedents, property values and large investors.

Thanks!!!!