One hallmark of the mortgage-banking crisis, robo-signing,

One hallmark of the mortgage-banking crisis, robo-signing, in which banks blindly accepted legal documents without checking them for accuracy or authenticity, has led to a series of lawsuits against large banks such as Bank of America and Citigroup.

(A) One hallmark of the mortgage-banking crisis, robo-signing, in which banks
(B) Robo-signing was one hallmark of the mortgage-banking crisis, in which banks
(C) Robo-signing, which was one hallmark of the mortgage-banking crisis and which banks
(D) One hallmark of the mortgage-banking crisis was robo-signing, in which banks
(E) One hallmark of the mortgage-banking crisis was robo-signing, and banks

OA A

Source: Veritas Prep