The diagram depicts a gas enclosed in a cylinder by a piston. The gas has a volume of $120\,\text{cm}^3$ and a pressure of $P$. The piston is then pushed slowly to the left, causing the gas volume to decrease to $30\,\text{cm}^3$. The temperature of the gas remains unchanged. What is the new pressure of the enclosed gas?
- A$\frac{P}{4}$
- B$\frac{P}{2}$
- C$P$
- D$4P$