5. C.

According to the differences between the outlets shown in the diagram, we know (1) is incorrect; by symmetry, we know (2) is correct;
Based on the first outlet having a flow rate of $\frac{1}{16}$, the second outlet having a flow rate of $\frac{1}{4}$, and the third outlet having a flow rate of $\frac{3}{8}$, the flow rate ratio of outlets 1, 2, and 3 is approximately $1: 4: 6$, so (3) is correct;

Noting that the flow rates of outlets 1 and 5 are $\frac{1}{16}$, the material wear rate is the slowest here, and the flow rate after the first split is $\frac{1}{2}$ (i.e., the flow rate of the two legs of the isosceles right triangle at the top of the purification tower is $\frac{1}{2}$). Therefore, the material wear rate of the top triangle of the purification tower is the fastest, so the time to replace the slowest-wearing triangular material is about 8 times the time to replace the fastest-wearing triangular material. Thus, (4) is correct.
5. Figure 2 shows the inside of a sewage purification tower. Sewage enters from the top and flows over the surface of purification materials shaped like isosceles right triangles, as indicated by the arrows in the figure. Each time the water flows, it has an equal chance of flowing along either leg of the triangle. After passing through four layers of purification, it flows into one of the five outlets at the bottom.
The following judgments:
(1) The water flow from the five outlets is the same;
(2) The water flow from outlet 2 is the same as the water flow from outlet 4;
(3) The ratio of water flow from outlets 1, 2, and 3 is approximately $1: 4: 6$;
(4) If the wear rate of the purification material is proportional to the amount of water flowing over its surface, then the slowest-replacement triangular material will last about 8 times longer than the fastest-replacement triangular material.
Among these, the correct judgments are ( ).
(A)(2)(3)
(B) (1)(3)(4)
(C) (2)(3)(4)
(D) (2) (4)