Final answer:
According to Archimedes' principle, the rubber ball displaces 12 lbs of water because it will float due to its lower density compared to water. This results in the displaced volume of water being larger than the volume of the ball itself.
Step-by-step explanation:
The question involves understanding Archimedes' principle, which states that the buoyant force on an object is equal to the weight of the fluid it displaces. Given that the rubber ball weighs 12 lbs and is 40% as dense as water, we can deduce that it will float because its density is less than water. Therefore, the weight of the water displaced by the rubber ball will be equal to the weight of the ball itself.
Since the ball is less dense than water, it will displace a greater volume of water to equal the weight of the 12 lbs rubber ball. This means that the correct answer to the question is 'the ball is displacing 12 lbs of water, the volume of this water is larger than the volume of the ball', which corresponds to option a).