E is awkard and wordy. Note that E has 3 commas whereas D conveys the meaning in two sentences separated by a single comma and also keeps the "rudimentary sense of vision" and the rating part together.

(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.

E is also wrong because the answer choice uses "its". "Its" is a possessive pronoun, for which it needs to have a possessive noun in the beginning to make sense of it. There isn't a possessive noun in the beginning, but only "a baby emerges...". The only way to make sense of the possessive pronoun (its) is if the answer choice began with the construction of "baby's vision", rather than "a baby" alone. Otherwise, the usage of "its" is out of place and has no direct referent.
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[quote]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 lind 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./quote]

A. is out. the 'it' is not clear as to its antecedent. This same unclear pronoun is later repeated. beginning with as and then the subject is 'it.'
B. This is better than A. Still the second part (or legally blind as an adult is referring to vision not the baby).
C. Also begins with as forcing the subject to be sense. Then it has a semicolon followed by a less than complete second part.
D. Good. We have the baby as the subject. then the second part is very clear with a clear subject.
E. The subject again is sense. The core of the sentence is "sense would be rated" The modifiers should not overwhelm the core of the sentence.

D. is best of the five. B is the least worst of the remainders.

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I m not quite sure of the possessive poison here sir..Do you have few more examples on this..

I have chosen D for this question:

A. This answer choice is confusing because of the pronoun "it." The sentence starts off using a subordinate clause, and the main clause starts with the first use of "it." However, this first "it" refers to the baby instead of the rudimentary sense of vision - this is incorrect. Also, the use of the coordinating conjunction "or" is supposed to separate 2 independent clauses. The second clause cannot stand alone, so the use of "or" is also incorrect in this case.

B. The only real mistake is the use of the coordinating conjunction "or." Again, it is supposed to separate 2 independent clauses. In this case, it tries to modify 20/500 - this is incorrect.

C. The verb-ing modifier "qualifying" comes after a semicolon - this makes no sense. Modifiers are usually separated from the clauses by commas. Since this modifier comes after a semicolon, it is supposed to act as an independent clause and because it doesn't, it is a sentence fragment.

D. This answer choice is correct - it clearly identifies the meaning of the sentence. The two sentences are separated by a semicolon and they are related.

E. The use of "which" seems to be misplaced - it should probably be modifying 20/500.

I am also confused about: As a baby emerges from the darkness of the "womb with a rudimentary" ....
"a rudimentary" seems to modify womb rather than baby?
Please clarify this construction.Thanks.
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The process of elimination is mentioned in red against each option.