What is the name of the welding made along the edges of two parallel plates?

The correct answer identifies the joint as an edge joint, which is precisely the type of welding used to join the edges of two parallel plates. In a typical edge joint, the plates are aligned so that their edges are in contact, allowing the weld to be made directly along this line. This method is particularly effective for creating a strong bond between plates, especially in applications where the structural integrity along the edge is critical.

In contrast, groove joints involve cuts made into one or both of the pieces to be joined, providing a space into which weld filler can be deposited; this is not limited to parallel plates. Fillet joints, on the other hand, typically involve the joining of two perpendicular plates and use a triangular cross-section of weld to fill the corner created by the two plates. Additionally, corner joints usually connect two pieces at an angle, typically at 90 degrees, rather than along the parallel edges.

Thus, the specific alignment and technique of welding along the edges of two parallel plates is quintessentially defined as an edge joint, making it the most appropriate answer in this context.