A simple, quick stitch that can be used to secure the entire length of a weft to a track is called the:

The correct answer is the overcast stitch. This stitch is specifically designed for securing fabric edges, making it particularly effective for securing the entire length of a weft to a track in weaving or extension applications. An overcast stitch involves looping the thread over the edge of the fabric, which provides a strong hold while keeping the weft in place. This technique helps prevent fraying and ensures that the extensions remain securely attached.

Other options may refer to different stitching techniques with distinct purposes. For instance, a double-lock stitch is used to create a more secure bond by locking two threads together, which can be effective but is not specifically the simplest or quickest method for the general task of securing wefts. The lock stitch is often employed in sewing machines for various sewing purposes but does not necessarily provide the same quick and effective method for securing wefts as the overcast stitch. The moving stitch is less commonly referred to in this context, making it less relevant for securing wefts. Therefore, the overcast stitch stands out as the most suitable and effective option for that specific task.