Sentence Correction (SC) | Re: New data from United States Forest Service ecologists show

Hello - Please pardon my lack of understanding here, I am unable to understand the explanation Dagh gave for option D and E. Specifically for the usage of "that".

I even tried to read the official explanation, which says - "That introduces a subordinate rather than main clause, making a sentence fragment; it has no referent; not having to extinguish is wordy and awkward." For D & "Introductory that makes a sentence fragment; that would not have been spent on extinguishing
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