In late 1997,the chambers inside the pyramid of the Pharaoh Menkaure at Giza were closed to visitors fo cleaning and repairing 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 in 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 then 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 mke the salt fron 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.


My doubt here is that in the correct option is 'them' not referring to 'tourists'?ans is E