The height of the water in each column will be a result of the Pressure of the fluid on the outer walls near that column. So, the water level will be lowest in the column that has the lowest Pressure.
Bernoulli's eqn, comparing columns 1 and 2:
P1 + density * g * h1 + 1/2 * density * v1^2 = P2 + density * g * h2 + 1/2 * density * v2^2
And continuity equation:
a1 * v1 = a2 * v2
h1 and h2 refer to the height of the fluid above some datum, which I think is negligible in this question. Betweens columns 1 and 2, the cross sectional area is decreasing. From the continuity equation, a1 > a2, so v2 > v1. Since v2 > v1, P1 > P2 to satisfy Bernoulli's equation describing conservation of energy. A lower pressure in column 2 will result in a lower height of water in column 2- this is different from the h2 variable in Bernoulli's equation.
Following this logic, column 4 has the smallest area, so it has the largest velocity of fluid flow (because the same amount of fluid has to get through a smaller area in the same amount of time -> it has to move faster!). With a larger velocity, the pressure will be decreased resulting in the lowest height of water in the column.