新prep1，186，大牛指教！

Laos
has a land area about the same as Great Britain but only 4 million in population, where many are members of hill tribes ensconced in the virtually inaccessible mountain valleys of the north.
A. about the same as Great Britain
but only 4 million in population, where many
B. of about the same size as Great Britain is, but in Laos
there is a population of only 4 million, and many
C. that is about the same size as Great Britain's land area, but in Laos
with a population of only 4 million people, many of them
D. comparable to the size of Great Britain
, but only 4 million in population, and many
E. comparable to that of Great Britain
but a population of only 4 million people, many of whom

答案是e，但是，but后面接了一个many  of whom的从句，没有主句谓语，怎么还平行呢？

谢谢了！！