23.int z=5； 24. 25. public void stuff1（int x） { 26. assert （x> 0）； 27. switch（x） { 28. case 2： x= 3； 29. default： assert false； } } 30. 31. private void stuff2（int y） { assert （y < 0）； } 32. 33. private void stuff3（） { assert （stuff4O）； } 34. 35. private boolean stuff4（） { z = 6； return false； } Which is true？（）
- A All of the assert statements are used appropriately.
- B Only the assert statement on line 31 is used appropriately.
- C The assert statements on lines 29 and 31 are used appropriately.
- D The assert statements on lines 26 and 29 are used appropriately.
- E The assert statements on lines 29 and 33 are used appropriately.
- F The assert statements on lines 29， 31， and 33 are used appropriately.
- G The assert statements on lines 26， 29， and 31 are used appropriately.