Choice is necessitated by the scarcity of resources.
Scarcity is the fundamental economic problem of having unlimited wants and needs in a world of limited resources. Because resources are limited, individuals, businesses, and societies must make choices about how to allocate those resources in the most efficient and effective way possible.
For example, an individual may have to choose between buying a new car or saving for retirement, because they cannot afford to do both. A business may have to choose between expanding its product line or investing in new technology. A society may have to choose between investing in education or healthcare.
In each case, the choices are necessitated by the scarcity of resources. Because resources are limited, we must make choices about how to allocate them in the most effective way possible to satisfy our unlimited wants and needs.