Since 1981, when the farm depression began, the number of acres overseen by professional farm-management companies have grown from 48 million to nearly 59 million, an area that is about Colorado's size.

a)have grown from 48 million to nearly 59 million, an area that is about Colorado's size.

b)have grown from 48 million to nearly 59 million, about the size of Colorado.

c)has grown from 48 million to nearly 59 million, an area about the size of Colorado.

d)has grown from 48 million up to nearly 59 million, an area about the size of Colorado.

e)has grown from 48 million up to nearly 59 million, about Colorado's size.

In choice C, the best answer, an area about the size of Colorado clearly describes a rough equivalence between the area of Colorado and the area overseen by the companies. In A and B, the plural verb have does not agree with the singular subject number. Choice A is also wordy, since that is can be deleted without loss of clarity. The absence of an area in B and E impairs clarity:.. 为什么这个地方的that可以省略？谢谢！