A sealed U-shaped tube holds a liquid of density $\rho$ that is at rest. On one side of the tube there is a gas at pressure $p_1$, and on the other side there is a gas at pressure $p_2$, as illustrated. The acceleration of free fall is $g$. Which equation is correct?
- A$p_1 = \rho g y$
- B$p_2 = \rho g (x - z)$
- C$p_1 - p_2 = \rho g (y - z)$
- D$p_1 + p_2 = \rho g x$