The sentence with an incorrect shift in pronoun-antecedent agreement is:
D Neither Julie nor Johnny were aware that his and her lives were about to change.
The antecedents "Julie" and "Johnny" are singular, so the correct verb should be "was" instead of "were." Additionally, it is better to maintain consistency in pronouns, potentially using "their" instead of "his and her" to refer back to both Julie and Johnny. A corrected version could be: "Neither Julie nor Johnny was aware that their lives were about to change."