The correct answer is A) One discharge phase begins before the previous discharge phase has been completed. The reason this is the correct answer is that the herringbone gear design of the pump creates a more continuous and steady discharge pressure compared to a simple spur gear pump. In a herringbone gear pump, the discharge phase of one set of gear teeth overlaps with the discharge phase of the next set of teeth, resulting in a more even and continuous flow of the pumped fluid. This overlapping discharge phase is what leads to the steadier discharge pressure, as opposed to the more pulsed discharge of a simple spur gear pump. The other answer choices are incorrect because they do not directly address the reason for the steadier discharge pressure in a herringbone gear pump.