A

Step 1: Understand that when the entire system falls freely, it experiences weightlessness.
Step 2: In a free-fall scenario, the water in both the test-tube and the vessel would exhibit the effects of inertia, meaning the water will not exert pressure on the test-tube walls.
Step 3: Thus, the water level in the test-tube will not remain fixed; instead, it will appear to rise (or will remain at the same level relative to the test-tube) due to the lack of gravitational pull acting on it.
Therefore, the water level in the test-tube remains unchanged relative to the water in the vessel (A).