According to the problem, water with the same height is injected into the container, that is, the water depth h is the same.

∫p =ρGH，

∴ pressure of water at the bottom of the container ∴ p a = p b；;

The two containers a and b have the same mass,

∴ Two containers are equal in weight,

As can be seen from the figure, the weight of water in container A is smaller than that in container B,

* Pressure on the ground

F=G=G container +G water,

When filled with water, press it on the table of the container:

F a < F B。

So choose C.