Digging in sediments in northern China, evidence has been gathered by scientists suggesting that complex life-forms emerged much earlier than they had previously thought.

(A) evidence has been gathered by scientists suggesting that complex life-forms emerged much earlier than they had

(B) evidence gathered by scientists suggests a much earlier emergence of complex life-forms than had been

(C) scientists have gathered evidence suggesting that complex life-forms emerged much earlier than

(D) scientists have gathered evidence that suggests a much earlier emergence of complex life-forms than that which was

(E) scientists have gathered evidence which suggests a much earlier emergence of complex life-forms than that