Đáp án sai trong các câu hỏi trên là:

1. **C**: "to allow a 4 year-old child to walk home alone." (Đúng: "to allow a 4-year-old child to walk home alone.")
2. **A**: "The Smiths are very proud of that their son..." (Đúng: "The Smiths are very proud that their son...")
3. **C**: "We called the baseball park up to ask that when the game was scheduled to begin..." (Đúng: "We called the baseball park up to ask when the game was scheduled to begin...")

Vậy nên, đáp án sai là: **A** cho câu 2.