Zimway I$.$ is a small$-$scale manufacturer of linen. Couture Corp., a big apparel brand, purchases linen from Zimway in large quantities. Zimway, otherwise, has very few clients, and most of them purchase linen occasionally and in minimal quantities. Therefore, business ties with Couture are crucial for Zimway's survival and success. In the context of the specific environment, which of the following concepts is illustrated in the scenario?