A quicker way to check this sentence is to say each option out loud and listen for what sounds natural to a native speaker, then confirm it with the underlying rule.
"Here is he" sounds off because English speakers invert word order after "here" only when the subject is a full noun, such as "here comes the train." With a pronoun subject like "he," the normal order stays: "here he is." That already rules out the first option.
Next, look at the spelling of the contraction. "Where's" stands for "Where is," so the apostrophe must sit right after the "e" in "Where," giving "Where's." Placing it after the "s," as in "Wheres'," does not stand for anything and is simply a spelling error.
Finally, look at the punctuation and tone. An exclamation mark signals the speaker is pointing something out with certainty, "right in front of us." Phrasing it as a question, "Is he here," clashes with that certainty, so that version does not fit either.
Once the wrong word order, the wrong apostrophe, and the mismatched question form are ruled out, only one version is left standing.
So, the correct answer is Where's Hari? Here he is, right in front of us!
Reading each option aloud, exactly as written, and noticing where the sentence first feels unnatural to a native speaker's ear is a quick way to work through this one.
Trusting the natural rhythm of each option and then checking the reason behind the stumble points to the same option every time.
So, the correct answer is Where's Hari? Here he is, right in front of us!