OG11, review 72题，请教

72. The gyrfalcon，an Arctic bird of prey, has survived a close brush with extinction；its numbers are now five-times greater than when the use of DDT was sharply restricted in the early 1970’s．

(A)  extinction；its numbers are now five times greater than

(B)  extinction：its numbers are now five times more than

(C)  extinction，their numbers now fivefold what they were

(D)  extinction，now with fivefold the numbers they had

(E)  extinction，now with numbers five times greater than

正确：A, 我选了B

OG解释B:The use of more instead of greater inappropriately implies there are now more numbers，rather than more gyrfalcons．

不明白啊，more than 就是指numbers,greater than 指gyrfalcons?

还有，有那位高手指点一下，number, numbers的用法，区别？

In B, the construction its numbers are... more is not idiomatic: there are more birds, but not more numbers.
        

解释得很清楚啊