Question 7
When an object floats in a fluid, what can be said about the weight of the fluid it displaces?
The right answer is the one marked above.
It equals the weight of the object. While it floats the upthrust equals the object's weight, and by Archimedes' principle that upthrust also equals the weight of the fluid displaced.
This holds whether the object floats partly or fully immersed. It does not hold for an object that sinks — there the weight of fluid displaced is less than the weight of the object.