Sentence Correction (SC) | Re: In late 1997, the chambers inside the pyramid of the Pharaoh

Hi,

In option E - "because moisture exhaled by tourists had raised the humidity within them to such levels that salt from the stone was crystallizing"

Isn't them an ambiguous pronoun? i.e. them has 2 possible antecedents - tourists & chambers. How do we know that them is referring to chambers?

Thanks!

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