A student measures the length of a spring. She then hangs different weights on the spring. For each weight, she records the spring’s length. The table gives her results. What is the extension of the spring 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$13\,\text{mm}$