27.   In 1929 relatively small declines in the market ruined many speculators having bought on margin; they had to sell, and their selling pushed other investors to the brink.

(A) speculators having bought on margin; they had to sell, and

(B) speculators who had bought on margin; having had to sell,

(C) speculators who had bought on margin; they had to sell, and

(D) speculators, those who had bought on margin; these speculators had to sell, and（C）

(E) speculators, who, having bought on margin and having to sell,

a不是更简洁么