50. As a baby emerges from the darkness of the womb with a rudimentary sense of vision, it would be rated about 20/500. or legally blind if it were an adult with such vision.
A. As a baby emerges from the darkness of the womb with a rudimentary sense of vision, it would be rated about 20/500, or legally blind if it were an adult with such vision.
B. A baby emerges from the darkness of the womb with a rudimentary sense of vision that would be rated about 20/500, or legally blind as an adult
C. As a baby emerges from the darkness of the womb, its rudimentary sense of vision would be rated about 20/500; qualifying it to be legally blind if an adult
D. A baby emerges from the darkness of the womb with a rudimentary sense of vision that would be rated about 20/500; an adult with such vision would be deemed legally blind.
E. As a baby emerges from the darkness of the womb, its rudimentary sense of vision, which would deemed legally blind for an adult, would be rated about 20/500.
 
1.  分号的使用：（一级排除C）
分号前后都必须是成分完整的句子
 
2.   代词：（二级排除A,B,E） 从句主句的逻辑主语一致

In choice A, it, the subject of the main clause, seems to refer to baby，当有代词时。考虑其逻辑意思的合理性

Similarly, choices B and E use awkward and ambiguous phrasing that suggests that the sense of vision, rather than an adult with 20/500 vision, would be
considered legally blind