Compare each option to 19.

• A: 20 ones = 20. 20 > 19. ✓
• B: 5 + 10 = 15. 15 < 19. ✗
• C: 10 + 4 = 14. 14 < 19. ✗
• D: 1 ten 2 ones = 12. 12 < 19. ✗

Final Answer: A: 20 ones