题目内容：

Gmat 语法
In 1997,despite an economy that marked its sixth full year of uninterrupted expansion with the lowest jobless rate in a quarter century,the number of United States citizens declaring themselves bankrupt has jumped by almost 20 percent,at 1.34 million.
(A) declaring themselves bankrupt has jumped by almost 20 percent,at
(B) declaring themselves bankrupt jumped by almost 20 percent,to
(C) who declared themselves bankrupt has jumped by almost 20 percent,to
(D) who declared themselves bankrupt jumped almost by 20 percent,at
(E) to declare themselves bankrupt jumped almost by 20 percent,at
我选的是C 但是错了.请各位朋友帮我分析