有人能分析一下这题A的语法结构吗 谢了

lllmmm

More than 300 rivers drain into Siberia's Lake Baikal, which holds 20 percent of the world's fresh water, more than all the North American Great Lakes combined.

(A) More than 300 rivers drain into Siberia's Lake Baikal, which holds 20 percent of the world's fresh water, more than all the North American Great Lakes combined.
(B) With 20 percent of the world's fresh water, that is more than all the North American Great Lakes combined, Siberia's Lake Baikal has more than 300 rivers that drain into it.
(C) Siberia's Lake Baikal, with more than 300 rivers draining into it, it holds more of the world's fresh water than all that of the North American Great Lakes combined, 20 percent.
(D) While more than 300 rivers drain into it, Siberia's Lake Baikal holds 20 percent of the world's fresh water, which is more than all the North American Great Lakes combined.
(E) More than all the North American Great Lakes combined, Siberia's Lake Baikal, with more than 300 rivers draining into it, holds 20 percent of the world's fresh water.
答案是A     但是A的结构看不懂

lonelyorchid

(A) More than 300 rivers drain into Siberia's Lake Baikal, [which holds 20 percent of the world's fresh water, (more than all the North American Great Lakes combined)].
(B) With 20 percent of the world's fresh water, [that] is more than all the North American Great Lakes combined, Siberia's Lake Baikal has more than 300 rivers that drain into it. THAT 没有指代。。。
(C) Siberia's Lake Baikal, with more than 300 rivers draining into it, [it] holds more of the world's fresh water than all that of the North American Great Lakes combined, 20 percent. IT重复了。。。
(D) [While] more than 300 rivers drain into it, Siberia's Lake Baikal holds 20 percent of the world's fresh water, which is more than all the North American Great Lakes combined. 用词不准确
(E) [More than all the North American Great Lakes combined], Siberia's Lake Baikal, with more than 300 rivers draining into it, holds 20 percent of the world's fresh water. 对象不明，离20 percent 太远了

wangjieava23

主句：More than 300 rivers drain into Siberia's Lake Baikal
which holds 20 percent of the world's fresh water 修饰Siberia's Lake Baikal
more than all the North American Great Lakes combined 进一步解释 Siberia's Lake Baikal holds 20 percent of the world's fresh water

lllmmm

more than all the North American Great Lakes combined 在句子中做什么成分？？