og12第六题求解

6. 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


(B) due to moisture that tourists had exhaled, thereby raising its humidity to such levels that


salt from the stone would crystallize


(C) because tourists were exhaling moisture, which had raised the humidity within them to levels


such that salt from the stone would crystallize


(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


(E) because moisture exhaled by tourists had raised the humidity within them to such levels that salt from the stone was crystallizing
d选项中raising是什么成分  另外 within them为什么可能被理解为tourist 这个选项中tourist是跟在by后面的啊  从句中的代词可能指代什么呢