read the sentence. emilia didnt realize the spy had gained the access codes until the security breach…

Brief Explanations:

Intensive pronouns (myself, yourself, himself, herself, itself, ourselves, yourselves, themselves) are used to emphasize the antecedent. In the correct option, "herself" emphasizes "Emilia". The first option correctly places the intensive pronoun right after the noun it emphasizes. The second option has an incorrect double - subject structure with "Emilia she". The third option has the intensive pronoun in the wrong position as it seems to modify "the access codes" instead of "Emilia". The fourth option has a wrong structure with "the spy she".

Answer:

Emilia herself didn't realize the spy had gained the access codes until the security breach happened.