请教一道语法题，有关consider

Babara Kingsolver's novel Pigs in Heaven is generally considered by critics __ best literary achievements.
A) as one of her
B) that is her
C) to be one of her
D) was one of her
答案说a
但不是说在toefl跟gmat语法中consider=regrad as
所以consider as 中as多余，出现就是错的
还有如果consider as成立那么consider to be 也算对吧？

谢谢大家赐教拉

consider sb sb/sth-> be considered  as sb/sth(加as是为了不会误会成consider sb/sth)

regard sb as sb/sth

consider sth to be/consider doing