The correct answer is C) life float. A life float is a rigid lifesaving device designed to support survivors in the water. It is a buoyant platform that can keep multiple people afloat in the event of an emergency, such as a vessel sinking or abandoning ship. Life floats are required safety equipment on many commercial vessels and are an important part of a vessel's lifesaving appliances. The other options are incorrect because: A) an inflatable liferaft is a portable, inflatable device, not a rigid lifesaving device; B) a survival capsule is an enclosed, rigid structure, not an open platform; and D) a rigid liferaft is a portable, rigid device, not specifically designed as a static, floating platform.