Since we want to find the fractions, we can assume some other length of the pipe which will make calculation easier. Take the length of the pipe to be 12-meter long (the least common multiple of 3 and 4.

In this case the branch would be cut at 3, 4, 6, 8, and 9 meters (in black are given fourths of the length and in red thirds of the length).

Distinct lengths would be: 3=3/12=1/4, 4-3=1=1/12 and 6-4=2=2/12=1/6 meters long pieces.

Answer: D.