A student records the length of a spring. She then hangs different weights from the spring. For each weight, she measures the spring’s length. Her results are given in the table. What extension does the spring have when a weight of $3.0\,\text{N}$ is attached to it?
- A$4\,\text{mm}$
- B$5\,\text{mm}$
- C$12\,\text{mm}$
- D$13\,\text{mm}$