The correct answer is B) To release the liferaft from the cradle automatically as the ship sinks. The purpose of the liferaft hydrostatic release is to automatically release the liferaft from its cradle or storage location when the ship sinks below a certain depth, usually around 4-6 meters. This ensures the liferaft will float free and be available for use by the crew, even if the ship goes down quickly. The hydrostatic release is a critical safety feature that allows the liferaft to deploy without any manual intervention, improving the chances of survival in an emergency. The other answer choices are incorrect. Option A is incorrect because the hydrostatic release does not inflate the liferaft automatically. Option C is incorrect because the hydrostatic release does not test the liferaft's integrity, it simply triggers the release mechanism. Option D is incorrect because the hydrostatic release does serve a specific and important purpose as described above.