For a liquid-in-glass thermometer, the liquid column measures 2.0 cm in length at $0^{\circ}\text{C}$ and becomes 10.0 cm longer when it is heated to $100^{\circ}\text{C}$. Starting from P, what is the length of the liquid column at $30^{\circ}\text{C}$?
- A2.3 cm
- B3.0 cm
- C5.0 cm
- D7.0 cm