The biggest whale is blue whale which grows to be about 29 meters long—the height of 9-s

问题补充：

The biggest whale is blue whale, which grows to be about 29 meters long—the height of 9-story building.

A. the; the

B. a; a

C. a; the

D. the; a

答案：

A. the; the

B. a; a

C. a; the

(答案→)D. the; a

解析：句意：最大的鲸是蓝鲸，它能长到大约29米长---它是9层楼的高度。the表示特指这种鲸；a表示泛指。故选D。