Pascal's principle: proof by contradiction. Points A and B are near each other at the same height

Question:

Pascal's principle: proof by contradiction. Points A and B are near each other at the same height in a fluid. Suppose P A > P B.
(a) Can both v A and v B be zero? Explain.
(b) Point C is just above point D in a static fluid. Suppose the pressure at C increases by an amount ΔP. What would happen if the pressure at D did not increase by the same amount?