Answer:
A. 1kg
Step-by-step explanation:
The block that would float highest in the water is:
A. 1kg
When an object is placed in water, it displaces an amount of water equal to its own weight. The buoyant force acting on the object is equal to the weight of the displaced water. For an object to float, the buoyant force must be greater than or equal to its weight.
Since all the blocks are the same size but have different masses, the block with the lowest mass (1kg) will have the lowest weight. This means it will displace the least amount of water and experience the smallest downward force due to its weight. As a result, the buoyant force will be greater than the weight of the 1kg block, allowing it to float highest in the water compared to the other blocks.