GMAT Sentence Correction (SC) | Re: Human mortality statistics on natural deaths suggest the possibility..

IMO, there are two decision points in terms of logical prediction/Idiom: I) reporting verb II) redundancy

1)to suggest is a reporting verb in this context, that requires a + THAT construction (check out substantive clauses). Additionally, there is no need for subjunctive, because its function is not to demand something but rather to report something; therefore the use of indicative is justified.
Another reason why it is logical to claim the need of " THAT " is because the sentence
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