When a solution approach is formulated, it is essentially a determination of whether a solution component will be purchased or created, or perhaps a combination of these two approaches. 

When it is decided to follow an approach where the solution component is created, it means that the requirements will be used by experts to develop, construct, or assemble the solution. When this approach is chosen, the requirements are at a level of detail that allows this approach to be chosen. This solution approach also includes any modifications required to existing solutions.

Let's look at a real-world example of creating a solution component.

A vehicle finance application system already exists within a financial institution. Based on stakeholder requirements, it is decided to construct and develop a new module for this system.

When it is decided to purchase a solution component to fulfill the requirements, it means that a third party will be involved in executing this solution approach. In most cases, the third party will manage and own the solution component, regardless of whether it is a service or a product. 

Let's look at a real-world example of purchasing a solution component.

An "off-the-shelf" accounting system is selected to meet the accounting requirements of the organization and will be delivered by a third-party vendor.

In most cases, however, the solution approach is a combination of creating and purchasing different parts of the overall solution and should be defined as such when defining the design options.