Final answer:
The correct welding position where a pipe assembly is placed vertically and welded horizontally without rotation is the 5G position, which is option d) 5G.
Step-by-step explanation:
In the 5G position, the pipe is fixed at one or both ends and the welding operator must travel in one of two directions, either vertical-up or vertical-down. Depending on the location of the pipe, the application may also require welding either overhead or in a flat position.
The given test is also being referred to is the 5G welding position, where a pipe assembly is placed vertically and the joint is welded in the horizontal position without rotating the assembly.
This test is one among the standard welding positions used globally to qualify welders for various types of welding work, especially for piping and tubing.
In this case, the correct option is d) 5G. The terms 1G, 2G, 3G, and 6G correspond to different welding positions, with each number-and-letter combination representing a specific position and technique required by the welder.