Question 3
When a partly immersed floating object is pushed right under by hand, why does the hand feel an extra upward force?
The right answer is the one marked above.
Pushed under, it displaces more water, so the upthrust now exceeds its weight. That leaves a resultant force acting upwards — and that is what the hand feels.
Neither the object's weight nor the water's density changes. The hand applies a downward force, not an upward one — the water does the pushing. Remove the hand and the object returns to its original level.