关于大捞句和指代不明的优先选择（绿色OG 680 48题）

Lee1993

在新东方上课的时候，李庆老师教的语法课，告诉我们两种句型容易错
1. 大捞句，即逗号接ing done---------这里只讨论“，doing”
2.指代不明，即逗号接which that-------这里只讨论“，which”
当时老师的原话是：“当同时出现时，指代不明比大捞句更好”。
但今天做到绿色OG 680 48题的时候，贴题：
48. It is called a sea, but the landlocked Caspian is actually the largest lake on Earth, which covers more than four times the surface area of its closest rival in size, North America's Lake Superior.

A. It is called a sea, but the landlocked Caspian is actually the largest lake on Earth, which covers
B. Although it is called a sea, actually the landlocked Caspian is the largest lake on Earth, which covers
C. Though called a sea, the landlocked Caspian is actually the largest lake on Earth, covering
D. Though called a sea but it actually is the largest lake on Earth, the landlocked Caspian covers
E. Despite being called a sea, the largest lake on Earth is actually the landlocked Caspian, covering

不讨论de，讨论adc，首先ab which如果按照老师的原话就是指代不清，而c是大捞句，即省略which + Be
但我觉得，当做gmat题，遇到“，+which”的时候应该默认为which修饰的是最近的那个名词，其次再考虑跳着修饰，即修饰前面的。
求NN出现解决下我的问题。
即，当出现指代不清和大捞句的时候，到底该怎么判断。

Lee1993

还想问一个问题。为什么OG答案上说ab选项的which，Grammatically, its antecedent cannot be the landlocked Caspian,so it must be either Earth or the largest lake on Earth.为何不能修饰Caspian

Lee1993

不要沉不要沉不要沉不要沉  
求NN来解答~~~~~~~

Lee1993

来人啊啊啊啊啊啊啊啊啊啊