Could be false. If the word in question was misspelled by an obvious typographical error and if the work it’s quoted in was modern, the editor may correct the spelling without explanation.

Could be false. The only rule we have about editing modern works is that it’s okay to correct obvious typographical errors without explanation. We have no information about when or how it might be acceptable to modernize an archaic spelling of a word in a modern work.

Could be false. We only know that an editor may modernize an archaic spelling of a word that is quoted from an older work if the archaic spelling occurs frequently. We also don’t have any information about whether or not the editor actually should do so.

Must be true. As shown below, by chaining the conditional claims, we see that “may modernize” is a necessary condition of “frequent occurrence.” As long as the punctuation occurs frequently, we know that the editor may modernize it.

Could be false. We know that if an editor modernizes more than one similar instance of quoted archaic punctuation, that editor should include a general statement in the preface. But that’s not a requirement if only one modernization was made.