A

Step 1: Use Bernoulli's principle which states that in a streamline flow, the total mechanical energy of the fluid remains constant.
Step 2: The pressure at the opening of the tube (where the water is flowing into) is less due to the higher velocity of the water.
Step 3: Calculate the height of the water column using the equation derived from Bernoulli's equation:
$$ P_{1} + \frac{1}{2} \rho v_{1}^2 + \rho gh_{1} = P_{2} + \frac{1}{2} \rho v_{2}^2 + \rho gh_{2} $$
Step 4: Assuming the inlet total pressure is atmospheric pressure and at outlet (inside the tube) is the gauge pressure:
$$ h = \frac{v^2}{2g} $$
This matches with option A.
Therefore, A.