GmatKiss wrote:The Audubon Society and other conservation groups, concerned over what they have perceived to be the serious threatening of the environment as posed by the policies of the government, are preparing for a major political effort.

(A) have perceived to be the serious threatening of the environment as
(B) perceived as the serious threat to the environment as it should be perceive
(C) perceive being the serious threat to the environment
(D) are perceiving as the serious threatening of the environment
(E) perceive as the serious threat to the environment