Fill in the blanks with the most appropriate option.
If a guitar string is pulled strongly, its amplitude of vibration (i) and the note heard is (ii). If it is pulled lightly, its amplitude of vibration (iii) and the note heard is (iv).
| (i) | (ii) | (iii) | (iv) | |
| A | Increases | Louder | Increases | Louder |
| B | Decreases | Softer | Decreases | Softer |
| C | Increases | Louder | Decreases | Softer |
| D | Decreases | Softer | Increases | Louder |