10月JJ SC不知道答案是什麼?

[evileyewl]

GWD 原题In 1981 children in the United States spent an average of slightly less than two and a half hours a week doing household chores; by 1997 they had spent nearly six hours a week.
A.chores; by 1997 they had spent nearly six hours a week
B.chores; by 1997 that figure had grown to nearly six hours a week
C. chores, whereas nearly six hours a week were spent in 1997
D. chores, compared with a figure of nearly six hours a week in 1997
E. chores, that figure growing to nearly six hours a week in 1997

[dibert8]

是 (B) 吧!
(A) they = children (in 1981) 不合理
(C) (D) (E) in 1997 改變句意