Answer:
The correct answer is passive transport
Explanation:
Passive transport is the transport in which the molecules move inside the cell along the concentration gradient without the use of energy.
So here there is a concentration gradient and the polar molecule is moving from its high concentration to its lower concentration which results in increment of that polar molecule inside the cell and it is also given that no energy is used in this case as ATP concentration is constant which shows that the transport is passive transport. In active transport ATP is used to transport molecules across cell membrane.