Correct Option: D

Hydraulic brake works on Pascal’s law which states that pressure exerted anywhere in a confined incompressible fluid is transmitted equally in all directions throughout the fluid such that the pressure variations remain the same. The wheel cylinder of hydraulic drum brakes acts as a double hydraulic press, multiplying the force on the fluid by the ratio of the area of the cylinder to the area of the supply line. Besides the muliplication of force achieved, Pascal’s principle guarantees that the pressure is transmitted equally to all parts of the enclosed fluid system.