Which of the fluids below would produce the highest pressure at the bottom of a tank for the same fluid depth?

a. mercury

b. air

c. water

d. helium?

The answer is a property of density. The higher the density, the higher the pressure at the bottom.

Pressure = mass / Area. So given that the 4 samples occupy the same area at the bottom, the mass is going to be the determining factor. Per given volume, mercury has the largest mass. The answer is A