求助两道语法题~

bobiouou

做了一些提，有些搞不明白，还请大牛们给解答下~~
1、To develop more accurate population forecasts, demographers have to know a great deal more than now about the social and economic determinants of fertility.

A:have to know a great deal more than now about the social and economic
B:have to know a great deal more than they do now about the social and economical
C:would have to know a great deal more than they do now about the social and economical
D:would have to know a great deal more than they do now about the social and economic
E:would have to know a great deal more than now about the social and economical
为什么答案是e,而不是b呢~~

2、The 32 species that make up the dolphin family are closely related to whales and in fact include the animal known as the killer whale, which can grow to be 30 feet long and is famous for its aggressive hunting pods.

A:include the animal known as the killer whale, which can grow to be 30 feet long and is
B:include the animal known as the killer whale, growing as big as 30 feet long and
C:include the animal known as the killer whale, growing up to 30 feet long and being
D:include the animal known as the killer whale, which can grow as big as 30 feet long and is
E:include the animal known as the killer whale, which can grow to be 30 feet long and it is
答案是a,那d选项是不是错在big 和long重复?~thanks