A movable piston seals a gas inside a cylinder. The gas column has a length of $20\,\text{cm}$ and the pressure in the cylinder is $p$. The piston is drawn out by $30\,\text{cm}$, so the gas column is now $50\,\text{cm}$ long. The gas temperature remains constant. What is the gas pressure now?
- A$0.40p$
- B$0.60p$
- C$1.5p$
- D$2.5p$