是否从句更好？？

23.   A
huge flying reptile that died out with the dinosaurs some 65 million years ago,
the Quetzalcoatlus had a wingspan of 36 feet, believed to be the largest
flying creature the world has ever seen.

(A) believed to be

(B) and that is
believed to be

(C) and it is
believed to have been

(D) which was, it
is believed,（C）

(E) which is
believed to be

 A huge flying reptile that died out with the dinosaurs some 65 million years ago,
        the Quetzalcoatlus had a wingspan of 36 feet,
        believed to be the largest flying creature the world has ever seen.

红色是一个短语，蓝色是个句子了。你选A是因为错误的把蓝色部分当作了红色部分的短语同位语，所以认为believe是谓语动词。实际上真正的谓语动词是蓝色部分的had.