The diagram depicts three vases, each having the same base area. In every vase, the water is the same depth. Which statement correctly describes the water pressures at points $P$, $Q$ and $R$?
- AThe pressure at point $P$ is the greatest.
- BThe pressure at point $Q$ is the least.
- CThe pressure at point $R$ is the greatest.
- DThe pressures at points $P$, $Q$ and $R$ are the same.