I would like to disagree to only this particular part of your explanation with all due respect.e-GMAT wrote:GMAT's stand on the issue of pronoun ambiguity is not as clear as it is for other grammatical errors. For this reason, unless the pronoun ambiguity is absolutely clear, it is suggested to arrive at the correct answer by using more obvious errors first and then use the pronoun ambiguity error on an as-needed basis.
This is one of those questions that can be very easily solved by using other more obvious errors: Below I have listed other errors:
In late 1997, the chambers inside the pyramid of the Pharaoh Menkaure at Giza were closed to visitors for cleaning and repair due to moisture exhaled by tourists, which raised its humidity to such levels so that salt from the stone was crystallizing and fungus was growing on the walls.
(A) due to moisture exhaled by tourists, which raised its humidity to such levels so that salt from the stone was crystallizing
1: Modifier Error - which refers to tourists
2: Pronoun Number - "its" should refer to "chambers" - thus number error.
3: Meaning - Use of "due to" implies that the closure of chambers was caused by moisture. This is not correct because closure was caused by the effect of the moisture as explained in choice E.
(B) due to moisture that tourists had exhaled, thereby raising its humidity to such levels that salt from the stone would crystallize
1: Verb tense - had exhaled is incorrect verb tense.
2: Parallelism - "salt would crystallize" is not parallel to "fungus was growing".
3: Meaning - Use of "due to" implies that the closure of chambers was caused by moisture. This is not correct because closure was caused by the effect of the moisture as explained in choice E.
(C) because tourists were exhaling moisture, which had raised the humidity within them to levels such that salt from the stone would crystallize
1: Verb Tense - " were exhaling" is incorrect verb tense; "had raised" is incorrect verb tense.
2: Parallelism - "salt would crystallize" is not parallel to "fungus was growing".
(D) because of moisture that was exhaled by tourists raising the humidity within them to levels so high as to make the salt from the stone crystallize
1: Modifier Error - "raising humidity" appears to modify "tourists" - incorrect
2: Parallelism - "salt crystallize" is not parallel to "fungus was growing".
(E) because moisture exhaled by tourists had raised the humidity within them to such levels that salt from the stone was crystallizing
Correct.
"(A) due to moisture exhaled by tourists, which raised its humidity to such levels so that salt from the stone was crystallizing
1: Modifier Error - which refers to tourists"
There is an exception rule to 'which'
which -> Modifies nearest noun ->
Exception:
1. Which can jump over essential modifier of the noun which "which" is referring.
2. The usage cannot be ambiguous .
3. Which cannot jump over a clause.
All the below examples are perfectly fine:
I bought a car (advertised on the local channel), which has latest gadgets.
I bought a car and a scooter, which has latest gadgets, on ebay.
I bought a car (that was advertised on the local channel), which has latest gadgets.

















