Final answer:
The volume of oil displaced is equal to the submerged volume of the body. To determine the exact volume, the total or submerged volume of the body must be known.
Step-by-step explanation:
The question relates to the concept of Archimedes' principle which states that the upward buoyant force exerted on a body immersed in a fluid is equal to the weight of the fluid the body displaces. Since three-quarters of a body's volume is immersed in oil with a density of 800 kg/m3, the volume of oil displaced will be equivalent to this same volume of the object submerged. However, to calculate the exact volume of the displaced oil, we need to know the total volume of the body or the volume of the submerged part.