GMAT Sentence Correction (SC) | Re: Balancing the need for sufficient food supplies

Dear Mike,

Thanks a lot for detailed explanation. Your answers stimulated more questions

1) Could 'that' refer to gerund also? Can I say "as THAT/THIS is for modern long-distance backpackers'??

2) In choice E, I subtitute the big sentence for 'it' but 'a concern' was omitted because it is understood or implied from the context. Am I right
Balancing the need for sufficient