OG 181

181. Because of the enormous research and development expenditures required to survive in the electronics industry, an industry marked by rapid innovation and volatile demand, such firms tend to be very large.

(A) to survive

(B) of firms to survive

(C) for surviving

(D) for survival（B）

(E) for firms’ survival

required of sb to do,   中文意思是什么啊？多谢