Explanation:

- The original sentence uses "isn't it?" as a tag question, but that’s incorrect because the subject is "she" (the boss), not "it."

- Option 1: "didn't she?" would be correct if the instruction was given in the past tense.

- Option 2: "hasn't she?" is correct because the instruction (to finish the project) is ongoing and aligns with the present perfect tense used in the main sentence.

- Option 3: "has she?" is not appropriate here since it's not a tag question that confirms or seeks agreement.

- Option 4: "no improvement" is incorrect as the original tag question doesn't match the subject.