Final answer:
A serger does overlocking, which is a stitch that sews over the edge of fabric for edging, hemming, or seaming, unlike a regular sewing machine. It also trims the fabric edge as it sews.
Step-by-step explanation:
The question asks about the functions that a serger, also known as an overlock machine, can perform compared to a regular sewing machine. A serger has capabilities that a typical sewing machine does not. Specifically, a serger is capable of creating an overlock stitch, which is a type of stitch that sews over the edge of one or two pieces of cloth for edging, hemming, or seaming. Additionally, a serger trims the edge of the fabric as it sews, which ensures a neat finish and saves time by performing two tasks at once.
Therefore, the correct answer to the question is (c) Overlock, though it's worth mentioning that trimming is also a function not typically carried out by a standard sewing machine. However, since the question specifically mentions functions related to stitching type, overlocking is the primary function that distinguishes a serger from a sewing machine.