Here we need to see the differences between a liquid and a gas, and how that affects the volume and effects of pressure on them.
The correct option is:
Gases are more readily compressed than liquids are because there is more space between the particles in a gas than in a liquid.
So we have two syringes, one with air and the other with water.
The student applies the same amount of pressure to both of them, but as water is denser than air, in a given change dV of volume in the syringe, the mass of water is larger than the mass of air.
This means that for the same pressure, we should expect the change in volume to be smaller in the syringe with water.
Why this happens?
Gases are more readily compressed than liquids are because there is more space between the particles in a gas than in a liquid.
This means that for the air is easier to be compressed (the distance between particles is larger, so the same pressure compresses more a gas than a liquid) and exit the syringe than for the water, and this translates to the change in volume per unit of pressure applied, which is larger for gases than liquids.
If you want to learn more, you can read:
https://brainly.com/question/1898264