Three different fluids are used in the manometer shown here. What is the pressure difference between the two sides of the manometer if fluid density and gravitational acceleration are considered?

a) Fluid 1 height - Fluid 2 height
b) Fluid 1 height + Fluid 2 height
c) Fluid 1 density + Fluid 2 density
d) Fluid 1 density - Fluid 2 density