### 🐍 Top 10 Python `append()` Quiz
Topic: Python Lists, `append()`, Nested Lists & Self-Referencing Lists
Test your Python knowledge with these output-based MCQs! 🚀
### Q1. What is the output?
A. 3
B. 4
C. 5
D. Error
### Q2. What is the output?
A. 2
B. 3
C. 4
D. Error
### Q3. What is the output?
A. \[1, 2, 3, 4\]
B. \[1, 2, \[3, 4\]\]
C. \[3, 4, 1, 2\]
D. \[1, 2, 4, 3\]
### Q4. What is the output?
A. 4
B. \[1, 2, 3, 4\]
C. None
D. True
### Q5. What is the output?
A. \[1, 2, 3, 4\]
B. \[\[1, 2\], \[3, 4\]\]
C. \[1, \[2, 3\], 4\]
D. Error
### Q6. What is the output?
A. 3
B. 4
C. 6
D. Error
### Q7. What is the output?
A. 2
B. 3
C. 4
D. 5
### Q8. What is the output?
A. 30
B. 40
C. 50
D. Error
### Q9. What is the output?
A. \[1, 2\]
B. \[3\]
C. \[1, 2, 3\]
D. Error
### Q10. What is the output?
A. True
B. False
C. None
D. Error
### 📌 Key Takeaways
| Method | Behavior |
| ------------------ | ------------------------- |
| append(x) | Adds one element |
| append([x, y]) | Adds a nested list |
| append(a) | Adds a self-reference |
| len(a) | Counts top-level elements |
| a.append(x) return | None |
